Methods for operating generator for digitally generating electrical signal waveforms and surgical instruments

ABSTRACT

Disclosed is a method of generating electrical signal waveforms by a generator. The generator includes a processor and a memory in communication with the processor. The memory defines a first and second table. The processor retrieves information from the first table defined in the memory, where the information is associated with a first wave shape of a first electrical signal waveform for performing a surgical procedure. The processor retrieves information from the second table defined in the memory, where the information is associated with a second wave shape of a second electrical signal waveform for performing a surgical procedure. The processor combines the first and second wave shapes to create a combined wave shape of an electrical signal waveform for performing a surgical procedure and the combined wave shape electrical signal waveform for performing a surgical procedure is delivered to a surgical instrument.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application claiming priority under35 U.S.C. § 120 to U.S. patent application Ser. No. 16/804,841, titledMETHODS FOR OPERATING GENERATOR FOR DIGITALLY GENERATING ELECTRICALSIGNAL WAVEFORMS AND SURGICAL INSTRUMENTS, filed Feb. 28, 2020, now U.S.Patent Application Publication No. 2020/0268433, which is a continuationapplication claiming priority under 35 U.S.C. § 120 to U.S. patentapplication Ser. No. 15/265,279, titled TECHNIQUES FOR OPERATINGGENERATOR FOR DIGITALLY GENERATING ELECTRICAL SIGNAL WAVEFORMS ANDSURGICAL INSTRUMENTS, filed Sep. 14, 2016, which issued on Apr. 21, 2020as U.S. Pat. No. 10,624,691, which claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application Ser. No. 62/235,260,titled GENERATOR FOR PROVIDING COMBINED RADIO FREQUENCY AND ULTRASONICENERGIES, filed Sep. 30, 2015, U.S. Provisional Patent Application Ser.No. 62/235,368, titled CIRCUIT TOPOLOGIES FOR GENERATOR, filed Sep. 30,2015, and U.S. Provisional Patent Application Ser. No. 62/235,466,titled SURGICAL INSTRUMENT WITH USER ADAPTABLE ALGORITHMS, filed Sep.30, 2015, the contents of each of which are incorporated herein byreference in their entirety.

TECHNICAL FIELD

The present disclosure generally relates to ultrasonic surgical systems,electrosurgical systems, and combination electrosurgical/ultrasonicsystems for performing surgical procedures such as coagulating, sealing,and/or cutting tissue. In particular, the present disclosure relates tocustomized algorithms for performing such procedures based on the typeof tissue being treated. More particularly, the present disclosurerelates to a generator which digitally generates electrical signalwaveforms for surgical instruments used to perform such procedures. Thedigital electrical signal waveforms are stored in a lookup table. Thegenerator digitally generates multiple electrical signal waveforms todrive multiple ultrasonic transducers.

BACKGROUND

Ultrasonic surgical instruments are finding increasingly widespreadapplications in surgical procedures by virtue of the unique performancecharacteristics of such instruments. Depending upon specific instrumentconfigurations and operational parameters, ultrasonic surgicalinstruments can provide substantially simultaneous cutting of tissue andhemostasis by coagulation, desirably minimizing patient trauma. Thecutting action is typically realized by an-end effector, or blade tip,at the distal end of the instrument, which transmits ultrasonic energyto tissue brought into contact with the end effector. Ultrasonicinstruments of this nature can be configured for open surgical use,laparoscopic, or endoscopic surgical procedures includingrobotic-assisted procedures.

Some surgical instruments utilize ultrasonic energy for both precisecutting and controlled coagulation. Ultrasonic energy cuts andcoagulates by vibrating a blade in contact with tissue. Vibrating athigh frequencies (e.g., 55,500 times per second), the ultrasonic bladedenatures protein in the tissue to form a sticky coagulum. Pressureexerted on tissue with the blade surface collapses blood vessels andallows the coagulum to form a hemostatic seal. The precision of cuttingand coagulation is controlled by the surgeon's technique and adjustingthe power level, blade edge, tissue traction, and blade pressure.

Electrosurgical devices for applying electrical energy to tissue inorder to treat and/or destroy the tissue are also finding increasinglywidespread applications in surgical procedures. An electrosurgicaldevice typically includes a handpiece, an instrument having adistally-mounted end effector (e.g., one or more electrodes). The endeffector can be positioned against the tissue such that electricalcurrent is introduced into the tissue. Electrosurgical devices can beconfigured for bipolar or monopolar operation. During bipolar operation,current is introduced into and returned from the tissue by active andreturn electrodes, respectively, of the end effector. During monopolaroperation, current is introduced into the tissue by an active electrodeof the end effector and returned through a return electrode (e.g., agrounding pad) separately located on a patient's body. Heat generated bythe current flowing through the tissue may form hemostatic seals withinthe tissue and/or between tissues and thus may be particularly usefulfor sealing blood vessels, for example. The end effector of anelectrosurgical device also may include a cutting member that is movablerelative to the tissue and the electrodes to transect the tissue.

Electrical energy applied by an electrosurgical device can betransmitted to the instrument by a generator in communication with thehandpiece. The electrical energy may be in the form of radio frequency(RF) energy that may be in a frequency range described in EN60601-2-2:2009+A11:2011, Definition 201.3.218—HIGH FREQUENCY. Forexample, the frequencies in monopolar RF applications are typicallyrestricted to less than 5 MHz. However, in bipolar RF applications, thefrequency can be almost anything. Frequencies above 200 kHz can betypically used for MONOPOLAR applications in order to avoid the unwantedstimulation of nerves and muscles which would result from the use of lowfrequency current. Lower frequencies may be used for BIPOLAR techniquesif the RISK ANALYSIS shows the possibility of neuromuscular stimulationhas been mitigated to an acceptable level. Normally, frequencies above 5MHz are not used in order to minimize the problems associated with HIGHFREQUENCY LEAKAGE CURRENTS. However, higher frequencies may be used inthe case of BIPOLAR techniques. It is generally recognized that 10 mA isthe lower threshold of thermal effects on tissue.

In application, an electrosurgical device can transmit low frequency RFenergy through tissue, which causes ionic agitation, or friction, ineffect resistive heating, thereby increasing the temperature of thetissue. Because a sharp boundary is created between the affected tissueand the surrounding tissue, surgeons can operate with a high level ofprecision and control, without sacrificing un-targeted adjacent tissue.The low operating temperatures of RF energy is useful for removing,shrinking, or sculpting soft tissue while simultaneously sealing bloodvessels. RF energy works particularly well on connective tissue, whichis primarily comprised of collagen and shrinks when contacted by heat.

Other electrical surgical instruments include, without limitation,irreversible and/or reversible electroporation, and/or microwavetechnologies, among others. Accordingly, the techniques disclosed hereinare applicable to ultrasonic, bipolar or monopolar RF (electrosurgical),irreversible and/or reversible electroporation, and/or microwave basedsurgical instruments, among others.

A challenge of using these medical devices is the inability to controland customize the power output depending on the type of tissue beingtreated by the devices. It would be desirable to provide a surgicalinstrument that overcomes some of the deficiencies of currentinstruments. The surgical system described herein overcomes thosedeficiencies.

As disclosed herein, a generator may be configured to generate an outputwaveform digitally and provide it to a surgical instrument such that thesurgical instrument may utilize the waveform for various tissue effects.The present disclosure provides for generator capabilities that promotetissue effects via wave-shaping and that drive RF and Ultrasonic energysimultaneously to a single surgical instrument or multiple surgicalinstruments.

Conventional generators for ultrasonic surgical instruments areconfigured to drive a single ultrasonic transducer. Shortcomings of suchconventional ultrasonic generators is the inability to drive multipleultrasonic transducers in one or more instruments simultaneously. Othershortcomings include the inability of ultrasonic generators to drivemultiple vibration modes in one instrument to achieve longer activelength at the tip of an ultrasonic blade to provide various tissueeffects.

SUMMARY

As disclosed herein, a generator may be configured to generate an outputwaveform digitally and provide it to a surgical instrument such that thesurgical instrument may utilize the waveform for various tissue effects.The present disclosure provides for generator capabilities that promotetissue effects via wave-shaping and that drive RF and Ultrasonic energysimultaneously to a single surgical instrument or multiple surgicalinstruments. The present disclosure also provides a generator configuredto generate wave-shaping to protect electrical output components of thegenerator when driving simultaneous RF and Ultrasonic waveforms.

In one aspect, a method of generating electrical signal waveforms by agenerator is provided. The generator comprises a digital processingcircuit, a memory circuit in communication with the digital processingcircuit, a digital synthesis circuit in communication with the digitalprocessing circuit and the memory circuit, and a digital-to-analogconverter (DAC) circuit. The memory circuit defines a lookup table. Themethod comprises storing, by the digital processing circuit, phasepoints of a digital electrical signal waveform in the lookup tabledefined by the memory circuit, wherein the digital electrical signalwaveform is represented by a predetermined number of phase points,wherein the predetermined number phase points define a predeterminedwave shape; receiving a clock signal by the digital synthesis circuit,and at each clock cycle: retrieving, by the digital processing circuit,a phase point from the lookup table; and converting, by the DAC circuit,the retrieved phase point to an analog signal.

In another aspect, a method of generating electrical signal waveforms bya generator is provided. The generator comprises a digital processingcircuit, a memory circuit in communication with the digital processingcircuit, a digital synthesis circuit in communication with the digitalprocessing circuit and the memory circuit, and a digital-to-analogconverter (DAC) circuit, where the memory circuit defines first andsecond lookup tables. The method comprises storing, by the digitalprocessing circuit, phase points of a first digital electrical signalwaveform in a first lookup table defined by the memory circuit, whereinthe first digital electrical signal waveform is represented by a firstpredetermined number of phase points, wherein the first predeterminednumber of phase points define a first predetermined wave shape; storing,by the digital processing circuit, phase points of a second digitalelectrical signal waveform in a second lookup table defined by thememory circuit, wherein the second digital electrical signal waveform isrepresented by a second predetermined number of phase points, whereinthe second predetermined number of phase points define a secondpredetermined wave shape; receiving, by the digital synthesis circuit, aclock signal, and at each clock cycle: retrieving, by the digitalsynthesis circuit, a phase point from the first lookup table;retrieving, by the digital synthesis circuit, a phase point from thesecond lookup table; and determining, by the digital processing circuit,whether to switch between the phase points of the first and secondelectrical signal waveforms or to synchronize the phase points of thefirst and second electrical signal waveforms.

In yet another a generator for generating electrical signal waveforms isprovided. The generator comprises a digital processing circuit; a memorycircuit in communication with the digital processing circuit, the memorycircuit defining a lookup table; a digital synthesis circuit incommunication with the digital processing circuit and the memorycircuit, the digital synthesis circuit receiving a clock signal; and adigital-to-analog converter (DAC) circuit. The digital processingcircuit configured to store phase points of a digital electrical signalwaveform in the lookup table defined by the memory circuit, wherein thedigital electrical signal waveform is represented by a predeterminednumber of phase points, wherein the predetermined number phase pointsdefine a predetermined wave shape; and retrieve a phase point from thelookup table at each clock cycle; and the DAC circuit configured toconvert the retrieved phase point to an analog signal.

In one aspect, a method of generating electrical signal waveforms by agenerator is provided. The generator comprises a digital processingcircuit, a memory circuit in communication with the digital processingcircuit, the memory circuit defining first and second lookup tables, adigital synthesis circuit in communication with the digital processingcircuit and the memory circuit, and a digital-to-analog converter (DAC).The method comprises storing, by the digital processing circuit, phasepoints of a first digital electrical signal waveform in a first lookuptable defined by the memory circuit, wherein the first digitalelectrical signal waveform is represented by a first predeterminednumber of phase points, wherein the first predetermined number of phasepoints define a first predetermined wave shape; storing, by the digitalprocessing circuit, phase points of a second digital electrical signalwaveform in a second lookup table defined by the memory circuit, whereinthe second digital electrical signal waveform is represented by a secondpredetermined number of phase points, wherein the second predeterminednumber of phase points define a second predetermined wave shape; andreceiving a clock signal by the digital synthesis circuit, and at eachclock cycle retrieving, by the digital synthesis circuit, a phase pointfrom the first lookup table; retrieving, by the digital synthesiscircuit, a phase point from the second lookup table; combining, by thedigital processing circuit, the phase point from the first lookup tablewith the phase point from the second lookup table to generate a combinedphase point; and converting, by the DAC circuit, the combined phasepoint into an analog signal; wherein the analog signal is configured todrive a first and second ultrasonic transducer.

In another aspect, a method of generating electrical signal waveforms bya generator is provided. The generator comprises a digital processingcircuit, a memory circuit in communication with the digital processingcircuit, the memory circuit defining first and second lookup tables, adigital synthesis circuit in communication with the digital processingcircuit and the memory circuit, and a digital-to-analog converter (DAC)circuit. The method comprises storing, by the digital processingcircuit, phase points of a first digital electrical signal waveform in afirst lookup table defined by the memory circuit, wherein the firstdigital electrical signal waveform is represented by a firstpredetermined number of phase points, wherein the first predeterminednumber of phase points define a first predetermined wave shape; storing,by the digital processing circuit, phase points of a second digitalelectrical signal waveform in a second lookup table defined by thememory circuit, wherein the second digital electrical signal waveform isrepresented by a second predetermined number of phase points, whereinthe second predetermined number of phase points define a secondpredetermined wave shape; and receiving a clock signal by the digitalsynthesis circuit, and at each clock cycle retrieving, by the digitalsynthesis circuit, a phase point from the first lookup table;retrieving, by the digital synthesis circuit, a phase point from thesecond lookup table; combining, by the digital processing circuit, thephase point from the first lookup table with the phase point from thesecond lookup table to generate a combined phase point; and converting,by the DAC circuit, the combined phase point into an analog signal;wherein the analog signal is configured to drive a plurality ofultrasonic operational modes of an ultrasonic device.

In yet another a generator for generating electrical signal waveforms isprovided. The generator comprises a digital processing circuit; a memorycircuit in communication with the digital processing circuit, the memorycircuit defining a lookup table; a digital synthesis circuit incommunication with the digital processing circuit and the memorycircuit, the digital synthesis circuit receiving a clock signal; and adigital-to-analog converter (DAC) circuit; the digital processingcircuit configured to: store phase points of a first digital electricalsignal waveform in a first lookup table defined by the memory circuit,wherein the first digital electrical signal waveform is represented by afirst predetermined number of phase points, wherein the firstpredetermined number of phase points define a first predetermined waveshape; and store phase points of a second digital electrical signalwaveform in a second lookup table defined by the memory circuit, whereinthe second digital electrical signal waveform is represented by a secondpredetermined number of phase points, wherein the second predeterminednumber of phase points define a second predetermined wave shape; at eachclock cycle the digital synthesis circuit is configured to: retrieve aphase point from the first lookup table; retrieve a phase point from thesecond lookup table; the digital processing circuit configured to:combine the phase point from the first lookup table with the phase pointfrom the second lookup table to generate a combined phase point; and theDAC circuit is configured to convert the combined phase point into ananalog signal; wherein the analog signal is configured to drive a firstand second ultrasonic transducer.

In one aspect, a method of generating electrical signal waveforms by agenerator is provided. The generator comprises a digital processingcircuit, a memory circuit in communication with the digital processingcircuit, a digital synthesis circuit in communication with the digitalprocessing circuit and the memory circuit, and a digital-to-analogconverter (DAC) circuit, the memory circuit defining first and secondlookup tables, the method comprising: storing, by the digital processingcircuit, phase points of a first digital electrical signal waveform in afirst lookup table defined by the memory circuit, wherein the firstdigital electrical signal waveform is represented by a firstpredetermined number of phase points, wherein the first predeterminednumber of phase points define a first predetermined wave shape; storing,by the digital processing circuit, phase points of a second digitalelectrical signal waveform in a second lookup table defined by thememory circuit, wherein the second digital electrical signal waveform isrepresented by a second predetermined number of phase points, whereinthe second predetermined number of phase points define a secondpredetermined wave shape; receiving, by the digital synthesis circuit, aclock signal, and at each clock cycle; retrieving, by the digitalsynthesis circuit, a phase point from the first lookup table;retrieving, by the digital synthesis circuit, a phase point from thesecond lookup table; combining, by the digital processing circuit, thefirst and second digital electrical signal waveforms to form a combineddigital electrical signal waveform; and modifying, by the digitalprocessing circuit, the combined digital electrical signal waveform toform a modified digital electrical signal waveform, wherein a peakamplitude of the modified digital electrical signal waveform does notexceed a predetermined amplitude value.

In another aspect, a method of generating electrical signal waveforms bya generator is provided. The generator comprises a digital processingcircuit, a memory circuit in communication with the digital processingcircuit, a digital synthesis circuit in communication with the digitalprocessing circuit and the memory circuit, and a digital-to-analogconverter (DAC) circuit, the memory circuit defining first and secondlookup tables, the method comprising: storing, by the digital processingcircuit, phase points of a first digital electrical signal waveform in afirst lookup table defined by the memory circuit, wherein the firstdigital electrical signal waveform is represented by a firstpredetermined number of phase points, wherein the first predeterminednumber of phase points define a first predetermined wave shape; storing,by the digital processing circuit, phase points of a second digitalelectrical signal waveform in a second lookup table defined by thememory circuit, wherein the second digital electrical signal waveform isrepresented by a second predetermined number of phase points, whereinthe second predetermined number of phase points define a secondpredetermined wave shape, wherein the second digital electrical signalwaveform is a function of the first digital electrical signal waveform;receiving, by the digital synthesis circuit, a clock signal, and at eachclock cycle; retrieving, by the digital synthesis circuit, a phase pointfrom the first lookup table; retrieving, by the digital synthesiscircuit, a phase point from the second lookup table; combining, by thedigital processing circuit, the first and second digital electricalsignal waveforms to form a combined digital electrical signal waveform;and modifying, by the digital processing circuit, the combined digitalelectrical signal waveform to form a modified digital electrical signalwaveform, wherein a peak amplitude of the modified digital electricalsignal waveform does not exceed a predetermined amplitude value.

In yet another a generator for generating electrical signal waveforms isprovided. The generator comprises a digital processing circuit, a memorycircuit in communication with the digital processing circuit, a digitalsynthesis circuit in communication with the digital processing circuitand the memory circuit, and a digital-to-analog converter (DAC) circuit,the memory circuit defining first and second lookup tables, the methodcomprising: storing, by the digital processing circuit, phase points ofa first digital electrical signal waveform in a first lookup tabledefined by the memory circuit, wherein the first digital electricalsignal waveform is represented by a first predetermined number of phasepoints, wherein the first predetermined number of phase points define afirst predetermined wave shape; storing, by the digital processingcircuit, phase points of a second digital electrical signal waveform ina second lookup table defined by the memory circuit, wherein the seconddigital electrical signal waveform is represented by a secondpredetermined number of phase points, wherein the second predeterminednumber of phase points define a second predetermined wave shape, whereinthe second digital electrical signal waveform is a function of the firstdigital electrical signal waveform; receiving, by the digital synthesiscircuit, a clock signal, and at each clock cycle; retrieving, by thedigital synthesis circuit, a phase point from the first lookup table;retrieving, by the digital synthesis circuit, a phase point from thesecond lookup table; modifying, by the digital processing circuit, afrequency of the first digital electrical signal waveform to form afrequency modified first digital electrical signal waveform; andcombining, by the digital processing circuit, the frequency modifiedfirst digital electrical signal waveform and the second digitalelectrical signal waveform to form a combined digital electrical signalwaveform.

FIGURES

The novel features of the described forms are set forth withparticularity in the appended claims. The described forms, however, bothas to organization and methods of operation, may be best understood byreference to the following description, taken in conjunction with theaccompanying drawings in which:

FIG. 1 illustrates one form of a surgical system comprising a generatorand various surgical instruments usable therewith;

FIG. 2 is a diagram of the combination electrosurgical and ultrasonicinstrument shown in FIG. 1 ;

FIG. 3 is a diagram of the surgical system shown in FIG. 1 ;

FIG. 4 is a model illustrating motional branch current in one form;

FIG. 5 is a structural view of a generator architecture in one form;

FIG. 6 illustrates one form of a drive system of a generator, whichcreates the ultrasonic electrical signal for driving an ultrasonictransducer;

FIG. 7 illustrates one form of a drive system of a generator comprisinga tissue impedance module;

FIG. 8 illustrates an example of a combined RF and ultrasonic energygenerator for delivering energy to a surgical instrument;

FIG. 9 is a diagram of a system for delivering combined RF andultrasonic energy to a plurality of surgical instruments;

FIG. 10 illustrates a communications architecture of a system fordelivering combined RF and ultrasonic energy to a plurality of surgicalinstruments;

FIG. 11 illustrates a communications architecture of a system fordelivering combined RF and ultrasonic energy to a plurality of surgicalinstruments;

FIG. 12 illustrates a communications architecture of a system fordelivering combined RF and ultrasonic energy to a plurality of surgicalinstruments;

FIG. 13 is a diagram of one form of a direct digital synthesis circuit;

FIG. 14 is a diagram of one form of a direct digital synthesis circuit;

FIG. 15 is an example graph of two waveforms of energy from a generator;

FIG. 16 is an example graph of the sum of the waveforms of FIG. 15 ;

FIG. 17 is an example graph of sum of the waveforms of FIG. 15 with theRF waveform dependent on the ultrasonic waveform;

FIG. 18 is an example graph of the sum of the waveforms of FIG. 15 withthe RF waveform being a function of the ultrasonic waveform;

FIG. 19 is an example graph of a complex RF waveform;

FIG. 20 illustrates one cycle of a digital electrical signal waveformshown in FIG. 18 ;

FIG. 21 is a logic flow diagram of a method of generating a digitalelectrical signal waveform according to one aspect;

FIG. 22 is a logic flow diagram of a method of generating a digitalelectrical signal waveform according to another aspect; and

FIG. 23 is a logic flow diagram of a method of generating a digitalelectrical signal waveform according to another aspect.

FIG. 24 is an example graph of two ultrasonic waveforms of energyproduced by a generator;

FIG. 25 is an example graph of the sum of the two ultrasonic waveformsof FIG. 24 ;

FIG. 26 is an example graph of sum of the waveforms of FIG. 24 with thehigher frequency ultrasonic waveform dependent on the lower frequencyultrasonic waveform;

FIG. 27 is an example graph of the sum of the waveforms of FIG. 24 withthe higher frequency ultrasonic waveform being a function of the lowerfrequency ultrasonic waveform;

FIG. 28 is an example graph of a complex ultrasonic waveform;

FIG. 29 illustrates one cycle of a digital electrical signal waveformshown in FIG. 27 ;

FIG. 30 is a logic flow diagram of a method of generating a digitalelectrical signal waveform according to one aspect; and

FIG. 31 is a logic flow diagram of a method of generating a digitalelectrical signal waveform according to one aspect.

FIG. 32 is a logic flow diagram of a method of generating an electricalsignal waveform configured to drive a surgical instrument and to protectoutput components of a generator according to one aspect;

FIG. 33 is a logic flow diagram of a method of generating a electricalsignal waveform configured to drive a surgical instrument and to protectoutput components of a generator according to another aspect; and

FIG. 34 is a logic flow diagram of a method of generating a digitalelectrical signal waveform configured to drive a surgical instrument andto protect output components of a generator according to another aspect.

DESCRIPTION

Before explaining various forms of surgical instruments in detail, itshould be noted that the illustrative forms are not limited inapplication or use to the details of construction and arrangement ofparts illustrated in the accompanying drawings and description. Theillustrative forms may be implemented or incorporated in other forms,variations and modifications, and may be practiced or carried out invarious ways. Further, unless otherwise indicated, the terms andexpressions employed herein have been chosen for the purpose ofdescribing the illustrative forms for the convenience of the reader andare not for the purpose of limitation thereof.

Further, it is understood that any one or more of thefollowing-described forms, expressions of forms, examples, can becombined with any one or more of the other following-described forms,expressions of forms, and examples.

Various forms are directed to improved ultrasonic and/or RFelectrosurgical instruments configured for effecting tissue dissecting,cutting, and/or coagulation during surgical procedures. In one form, anultrasonic and/or RF electrosurgical instruments may be configured foruse in open surgical procedures, but has applications in other types ofsurgery, such as laparoscopic, endoscopic, and robotic-assistedprocedures. Versatile use is facilitated by selective use of ultrasonicenergy.

This application is related to the following commonly owned patentapplication filed Sep. 14, 2016:

-   -   U.S. patent application Ser. No. 15/265,293, titled TECHNIQUES        FOR CIRCUIT TOPOLOGIES FOR COMBINED GENERATOR, by Wiener et al.,        now U.S. Patent Application Publication No. 2017/0086910.

This application also is related to the following commonly owned patentapplications filed on Sep. 7, 2016:

-   -   U.S. patent application Ser. No. 15/258,570, titled CIRCUIT        TOPOLOGIES FOR COMBINED GENERATOR, by Wiener et al., now U.S.        Patent Application Publication No. 2017/0086908;    -   U.S. patent application Ser. No. 15/258,578, titled CIRCUITS FOR        SUPPLYING ISOLATED DIRECT CURRENT (DC) VOLTAGE TO SURGICAL        INSTRUMENTS, by Wiener et al., now U.S. Patent Application        Publication No. 2017/0086911;    -   U.S. patent application Ser. No. 15/258,586, titled FREQUENCY        AGILE GENERATOR FOR A SURGICAL INSTRUMENT, by Yates et al., now        U.S. Patent Application Publication No. 2017/0086909;    -   U.S. patent application Ser. No. 15/258,598, titled METHOD AND        APPARATUS FOR SELECTING OPERATIONS OF A SURGICAL INSTRUMENT        BASED ON USER INTENTION, by Asher et al., now U.S. Patent        Application Publication No. 2017/0086876;    -   U.S. patent application Ser. No. 15/258,569, titled GENERATOR        FOR DIGITALLY GENERATING ELECTRICAL SIGNAL WAVEFORMS FOR        ELECTROSURGICAL AND ULTRASONIC SURGICAL INSTRUMENTS, by Wiener        et al., now U.S. Pat. No. 10,194,973;    -   U.S. patent application Ser. No. 15/258,611, titled GENERATOR        FOR DIGITALLY GENERATING COMBINED ELECTRICAL SIGNAL WAVEFORMS        FOR ULTRASONIC SURGICAL INSTRUMENTS, by Wiener et al., now U.S.        Patent Application Publication No. 2017/0086912;    -   U.S. patent application Ser. No. 15/258,650, titled PROTECTION        TECHNIQUES FOR GENERATOR FOR DIGITALLY GENERATING        ELECTROSURGICAL AND ULTRASONIC DIGITAL ELECTRICAL SIGNAL        WAVEFORMS, by Yates et al., now U.S. Patent Application        Publication No. 2017/0086913;        each of which is incorporated herein by reference in its        entirety.

This application also is related to the following commonly owned patentapplications filed on Jun. 9, 2016:

-   -   U.S. patent application Ser. No. 15/177,430, titled SURGICAL        INSTRUMENT WITH USER ADAPTABLE TECHNIQUES, now U.S. Patent        Application Publication No. 2017/0000541;    -   U.S. patent application Ser. No. 15/177,439, titled SURGICAL        INSTRUMENT WITH USER ADAPTABLE TECHNIQUES BASED ON TISSUE TYPE,        now U.S. Patent Application Publication No. 2017/0000516;    -   U.S. patent application Ser. No. 15/177,449, titled SURGICAL        SYSTEM WITH USER ADAPTABLE TECHNIQUES EMPLOYING MULTIPLE ENERGY        MODALITIES BASED ON TISSUE, now U.S. Patent Application        Publication No. 2017/0000553;    -   U.S. patent application Ser. No. 15/177,456, titled SURGICAL        SYSTEM WITH USER ADAPTABLE TECHNIQUES BASED ON TISSUE IMPEDANCE,        now U.S. Patent Application Publication No. 2017/0000542;    -   U.S. patent application Ser. No. 15/177,466, titled SURGICAL        SYSTEM WITH USER ADAPTABLE TECHNIQUES EMPLOYING SIMULTANEOUS        ENERGY MODALITIES BASED ON TISSUE PARAMETERS, now U.S. Patent        Application Publication No. 2017/0000554;        each of which is incorporated herein by reference in its        entirety.

The various forms will be described in combination with an ultrasonicinstrument as described herein. Such description is provided by way ofexample, and not limitation, and is not intended to limit the scope andapplications thereof. For example, any one of the described forms isuseful in combination with a multitude of ultrasonic instrumentsincluding those described in, for example, U.S. Pat. Nos. 5,938,633;5,935,144; 5,944,737; 5,322,055; and 5,449,370, which are eachincorporated by reference herein in their entirety.

As will become apparent from the following description, it iscontemplated that forms of the surgical instruments described herein maybe used in association with an oscillator unit of a surgical system,whereby ultrasonic energy from the oscillator unit provides the desiredultrasonic actuation for the present surgical instrument. It is alsocontemplated that forms of the surgical instrument described herein maybe used in association with a signal generator unit of a surgicalsystem, whereby RF electrical energy, for example, is used to providefeedback to the user regarding the surgical instrument. The ultrasonicoscillator and/or the signal generator unit may be non-detachablyintegrated with the surgical instrument or may be provided as separatecomponents, which can be electrically attachable to the surgicalinstrument.

One form of the present surgical apparatus is particularly configuredfor disposable use by virtue of its straightforward construction.However, it is also contemplated that other forms of the presentsurgical instrument can be configured for non-disposable or multipleuses. Detachable connection of the present surgical instrument with anassociated oscillator and signal generator unit is presently disclosedfor single-patient use for illustrative purposes only. However,non-detachable integrated connection of the present surgical instrumentwith an associated oscillator and/or signal generator unit is alsocontemplated. Accordingly, various forms of the presently describedsurgical instruments may be configured for single use and/or multipleuse with either detachable and/or non-detachable integral oscillatorand/or signal generator unit, without limitation, and all combinationsof such configurations are contemplated to be within the scope of thepresent disclosure.

In one aspect, the desired wave shape may be digitized by 1024 phasepoints, which are stored in a table, such as, for example, a directdigital synthesis table with a field programmable gate array (FPGA) ofthe generator. The generator software and digital controls command theFPGA to scan the addresses in this table at the frequency of interestwhich in turn provides varying digital input values to a DAC circuitthat feeds to power amplifier. This method enables generatingpractically any (or many) types of wave shapes fed into tissue.Furthermore, multiple wave shape tables can be created, stored andapplied to tissue.

According to various aspects, a method comprises creating various typesof lookup tables in memory such as lookup tables generated by directdigital synthesis (DDS) circuit and stored within FPGAs, for example.Waveforms may be stored in the DDS table or tables as particular waveshapes. Examples of wave shapes in the RF/Electrosurgery tissuetreatment field include high crest factor RF signals, which may be usedfor surface coagulation in an RF mode, for example, low crest factor RFsignals, which may be used for deeper penetration into tissue in an RFmode, for example, and waveforms that promote efficient touch-upcoagulation, for example. In one aspect, the crest factor (CF) may bedefined as the ratio of the peak signal to the root-mean-square (RMS)signal.

The present disclosure provides for the creation of multiple wave shapetables that allow for switching on the fly, either manually orautomatically, between the wave shapes based on tissue effect desired.Switching could be based on tissue parameters, such as, for example,tissue impedance and/or other factors. In addition to a traditional sinewave shape, in one aspect a generator may be configured to provide awave shape that maximizes the power into tissue per cycle. According toone aspect, the wave shape may be a trapezoid wave, a sine or cosinewave, a square wave, a triangle wave, or any combination thereof. In oneaspect, a generator may be configured to provide a wave shape or shapesthat are synchronized in such way that they make maximizing powerdelivery in the case that both RF and ultrasonic energy modalities aredriven, either simultaneously or sequentially. In one aspect, agenerator may be configured to provide a waveform that drives bothultrasonic and RF therapeutic energy simultaneously while maintainingultrasonic frequency lock. In one aspect, the generator may contain orbe associated with a device that provides a circuit topology thatenables simultaneously driving RF and ultrasonic energy. In one aspect,a generator may be configured to provide custom wave shapes that arespecific to a surgical instrument and the tissue effects provided bysuch a surgical instrument. Furthermore, the waveforms may be stored ina generator non-volatile memory or in an instrument memory, such as, forexample, an electrically erasable programmable read-only memory(EEPROM). The waveform or waveforms may be fetched upon instrumentconnection to a generator.

With reference to FIGS. 1-5 , one form of a surgical system 10 includinga surgical instrument is illustrated. FIG. 1 illustrates one form of asurgical system 10 comprising a generator 100 and various surgicalinstruments 104, 106, 108 usable therewith, where the surgicalinstrument 104 is an ultrasonic surgical instrument, the surgicalinstrument 106 is an RF electrosurgical instrument 106, and themultifunction surgical instrument 108 is a combination ultrasonic/RFelectrosurgical instrument. FIG. 2 is a diagram of the multifunctionsurgical instrument 108 shown in FIG. 1 . With reference to both FIGS. 1and 2 , the generator 100 is configurable for use with a variety ofsurgical instruments.

According to various forms, the generator 100 may be configurable foruse with different surgical instruments of different types including,for example, ultrasonic surgical instruments 104, RF electrosurgicalinstruments 106, and multifunction surgical instruments 108 thatintegrate RF and ultrasonic energies delivered simultaneously from thegenerator 100. Although in the form of FIG. 1 , the generator 100 isshown separate from the surgical instruments 104, 106, 108 in one form,the generator 100 may be formed integrally with any of the surgicalinstruments 104, 106, 108 to form a unitary surgical system. Thegenerator 100 comprises an input device 110 located on a front panel ofthe generator 100 console. The input device 110 may comprise anysuitable device that generates signals suitable for programming theoperation of the generator 100.

FIG. 1 illustrates a generator 100 configured to drive multiple surgicalinstruments 104, 106, 108. The first surgical instrument 104 is anultrasonic surgical instrument 104 and comprises a handpiece 105 (HP),an ultrasonic transducer 120, a shaft 126, and an end effector 122. Theend effector 122 comprises an ultrasonic blade 128 acoustically coupledto the ultrasonic transducer 120 and a clamp arm 140. The handpiece 105comprises a trigger 143 to operate the clamp arm 140 and a combinationof the toggle buttons 134 a, 134 b, 134 c to energize and drive theultrasonic blade 128 or other function. The toggle buttons 134 a, 134 b,134 c can be configured to energize the ultrasonic transducer 120 withthe generator 100.

Still with reference to FIG. 1 , the generator 100 also is configured todrive a second surgical instrument 106. The second surgical instrument106 is an RF electrosurgical instrument and comprises a handpiece 107(HP), a shaft 127, and an end effector 124. The end effector 124comprises electrodes in the clamp arms 142 a, 142 b and return throughan electrical conductor portion of the shaft 127. The electrodes arecoupled to and energized by a bipolar energy source within the generator100. The handpiece 107 comprises a trigger 145 to operate the clamp arms142 a, 142 b and an energy button 135 to actuate an energy switch toenergize the electrodes in the end effector 124.

Still with reference to FIG. 1 , the generator 100 also is configured todrive a multifunction surgical instrument 108. The multifunctionsurgical instrument 108 comprises a handpiece 109 (HP), a shaft 129, andan end effector 125. The end effector comprises an ultrasonic blade 149and a clamp arm 146. The ultrasonic blade 149 is acoustically coupled tothe ultrasonic transducer 120. The handpiece 109 comprises a trigger 147to operate the clamp arm 146 and a combination of the toggle buttons 137a, 137 b, 137 c to energize and drive the ultrasonic blade 149 or otherfunction. The toggle buttons 137 a, 137 b, 137 c can be configured toenergize the ultrasonic transducer 120 with the generator 100 andenergize the ultrasonic blade 149 with a bipolar energy source alsocontained within the generator 100.

With reference to both FIGS. 1 and 2 , the generator 100 is configurablefor use with a variety of surgical instruments. According to variousforms, the generator 100 may be configurable for use with differentsurgical instruments of different types including, for example, theultrasonic surgical instrument 104, the RF electrosurgical instrument106, and the multifunction surgical instrument 108 that integrate RF andultrasonic energies delivered simultaneously from the generator 100.Although in the form of FIG. 1 , the generator 100 is shown separatefrom the surgical instruments 104, 106, 108, in one form, the generator100 may be formed integrally with any one of the surgical instruments104, 106, 108 to form a unitary surgical system. The generator 100comprises an input device 110 located on a front panel of the generator100 console. The input device 110 may comprise any suitable device thatgenerates signals suitable for programming the operation of thegenerator 100. The generator 100 also may comprise one or more outputdevices 112.

With reference now to FIG. 2 , the generator 100 is coupled to themultifunction surgical instrument 108. The generator 100 is coupled tothe ultrasonic transducer 120 and electrodes located in the clamp arm146 via a cable 144. The ultrasonic transducer 120 and a waveguideextending through a shaft 129 (waveguide not shown in FIG. 2 ) maycollectively form an ultrasonic drive system driving an ultrasonic blade149 of an end effector 125. The end effector 125 further may comprise aclamp arm 146 to clamp tissue located between the clamp arm 146 and theultrasonic blade 149. The clamp arm 146 comprises one or more than onean electrode coupled to the a pole of the generator 100 (e.g., apositive pole). The ultrasonic blade 149 forms the second pole (e.g.,the negative pole) and is also coupled to the generator 100. RF energyis applied to the electrode(s) in the clamp arm 146, through the tissuelocated between the clamp arm 146 and the ultrasonic blade 149, andthrough the ultrasonic blade 149 back to the generator 100 via the cable144. In one form, the generator 100 may be configured to produce a drivesignal of a particular voltage, current, and/or frequency output signalthat can be varied or otherwise modified with high resolution, accuracy,and repeatability suitable for driving an ultrasonic transducer 120 andapplying RF energy to tissue.

Still with reference to FIG. 2 , It will be appreciated that themultifunction surgical instrument 108 may comprise any combination ofthe toggle buttons 137 a, 137 b, 134 c. For example, the multifunctionsurgical instrument 108 could be configured to have only two togglebuttons: a toggle button 137 a for producing maximum ultrasonic energyoutput and a toggle button 137 b for producing a pulsed output at eitherthe maximum or less than maximum power level. In this way, the drivesignal output configuration of the generator 100 could be 5 continuoussignals and 5 or 4 or 3 or 2 or 1 pulsed signals. In certain forms, thespecific drive signal configuration may be controlled based upon, forexample, EEPROM settings in the generator 100 and/or user power levelselection(s).

In certain forms, a two-position switch may be provided as analternative to a toggle button 137 c. For example, the multifunctionsurgical instrument 108 may include a toggle button 137 a for producinga continuous output at a maximum power level and a two-position togglebutton 137 b. In a first detented position, toggle button 137 b mayproduce a continuous output at a less than maximum power level, and in asecond detented position the toggle button 137 b may produce a pulsedoutput (e.g., at either a maximum or less than maximum power level,depending upon the EEPROM settings). Any one of the buttons 137 a, 137b, 137 c may be configured to activate RF energy and apply the RF energyto the end effector 125.

Still with reference to FIG. 2 , forms of the generator 100 may enablecommunication with instrument-based data circuits. For example, thegenerator 100 may be configured to communicate with a first data circuit136 and/or a second data circuit 138. For example, the first datacircuit 136 may indicate a burn-in frequency slope, as described herein.Additionally or alternatively, any type of information may becommunicated to second data circuit for storage therein via a datacircuit interface (e.g., using a logic device). Such information maycomprise, for example, an updated number of operations in which theinstrument has been used and/or dates and/or times of its usage. Incertain forms, the second data circuit may transmit data acquired by oneor more sensors (e.g., an instrument-based temperature sensor). Incertain forms, the second data circuit may receive data from thegenerator 100 and provide an indication to a user (e.g., a lightemitting diode (LED) indication or other visible indication) based onthe received data. The second data circuit 138 contained in themultifunction surgical instrument 108. In some forms, the second datacircuit 138 may be implemented in a many similar to that of the firstdata circuit 136 described herein. An instrument interface circuit maycomprise a second data circuit interface to enable this communication.In one form, the second data circuit interface may comprise a tri-statedigital interface, although other interfaces also may be used. Incertain forms, the second data circuit may generally be any circuit fortransmitting and/or receiving data. In one form, for example, the seconddata circuit may store information pertaining to the particular surgicalinstrument 104, 106, 108 with which it is associated. Such informationmay include, for example, a model number, a serial number, a number ofoperations in which the surgical instrument 104, 106, 108 has been used,and/or any other type of information. In the example of FIG. 2 , thesecond data circuit 138 may store information about the electricaland/or ultrasonic properties of an associated ultrasonic transducer 120,end effector 125, ultrasonic energy drive system, or RF electrosurgicalenergy drive system. Various processes and techniques described hereinmay be executed by a generator. It will be appreciated, however, that incertain example forms, all or a part of these processes and techniquesmay be performed by internal logic 139 located in the multifunctionsurgical instrument 108.

FIG. 3 is a diagram of the surgical system 10 of FIG. 1 . In variousforms, the generator 100 may comprise several separate functionalelements, such as modules and/or blocks. Different functional elementsor modules may be configured for driving the different kinds of surgicalinstruments 104, 106, 108. For example, an ultrasonic drive circuit 114may drive ultrasonic devices such as the surgical instrument 104 via acable 141. An electrosurgery/RF drive circuit 116 may drive the RFelectrosurgical instrument 106 via a cable 133. The respective drivecircuits 114, 116, 118 may be combined as a combined RF/ultrasonic drivecircuit 118 to generate both respective drive signals for drivingmultifunction surgical instruments 108 via a cable 144. In variousforms, the ultrasonic drive circuit 114 and/or the electrosurgery/RFdrive circuit 116 each may be formed integrally or externally with thegenerator 100. Alternatively, one or more of the drive circuits 114,116, 118 may be provided as a separate circuit module electricallycoupled to the generator 100. (The drive circuits 114, 116, 118 areshown in phantom to illustrate this option.) Also, in some forms, theelectrosurgery/RF drive circuit 116 may be formed integrally with theultrasonic drive circuit 114, or vice versa. Also, in some forms, thegenerator 100 may be omitted entirely and the drive circuits 114, 116,118 may be executed by processors or other hardware within therespective surgical instruments 104, 106, 108.

In other forms, the electrical outputs of the ultrasonic drive circuit114 and the electrosurgery/RF drive circuit 116 may be combined into asingle electrical signal capable of driving the multifunction surgicalinstrument 108 simultaneously with electrosurgical RF and ultrasonicenergies. This single electrical drive signal may be produced by thecombination drive circuit 118. The multifunction surgical instrument 108comprises an ultrasonic transducer 120 coupled to an ultrasonic bladeand one or more electrodes in the end effector 125 to receive ultrasonicand electrosurgical RF energy. The multifunction surgical instrument 108comprises signal processing components to split the combinedRF/ultrasonic energy signal such that the RF signal can be delivered tothe electrodes in the end effector 125 and the ultrasonic signal can bedelivered to the ultrasonic transducer 120.

In accordance with the described forms, the ultrasonic drive circuit 114may produce a drive signal or signals of particular voltages, currents,and frequencies, e.g., 55,500 cycles per second (Hz). The drive signalor signals may be provided to the ultrasonic surgical instrument 104,and specifically to the ultrasonic transducer 120, which may operate,for example, as described above. The ultrasonic transducer 120 and awaveguide extending through the shaft 126 (waveguide not shown) maycollectively form an ultrasonic drive system driving an ultrasonic blade128 of an end effector 122. In one form, the generator 100 may beconfigured to produce a drive signal of a particular voltage, current,and/or frequency output signal that can be stepped or otherwise modifiedwith high resolution, accuracy, and repeatability.

The generator 100 may be activated to provide the drive signal to theultrasonic transducer 120 in any suitable manner. For example, thegenerator 100 may comprise a foot switch 130 coupled to the generator100 via a foot switch cable 132. A clinician may activate the ultrasonictransducer 120 by depressing the foot switch 130. In addition, orinstead of the foot switch 130 some forms of the ultrasonic surgicalinstrument 104 may utilize one or more switches positioned on thehandpiece that, when activated, may cause the generator 100 to activatethe ultrasonic transducer 120. In one form, for example, the one or moreswitches may comprise a pair of toggle buttons 137 a, 137 b (FIG. 2 ),for example, to determine an operating mode of the ultrasonic surgicalinstrument 104. When the toggle button 137 a is depressed, for example,the generator 100 may provide a maximum drive signal to the ultrasonictransducer 120, causing it to produce maximum ultrasonic energy output.Depressing toggle button 137 b may cause the generator 100 to provide auser-selectable drive signal to the ultrasonic transducer 120, causingit to produce less than the maximum ultrasonic energy output.

Additionally or alternatively, the one or more switches may comprise atoggle button 137 c that, when depressed, causes the generator 100 toprovide a pulsed output. The pulses may be provided at any suitablefrequency and grouping, for example. In certain forms, the power levelof the pulses may be the power levels associated with toggle buttons 137a, 137 b (maximum, less than maximum), for example.

It will be appreciated that the ultrasonic surgical instrument 104and/or the multifunction surgical instrument 108 may comprise anycombination of the toggle buttons 137 a, 137 b, 137 c. For example, themultifunction surgical instrument 108 could be configured to have onlytwo toggle buttons: a toggle button 137 a for producing maximumultrasonic energy output and a toggle button 137 c for producing apulsed output at either the maximum or less than maximum power level. Inthis way, the drive signal output configuration of the generator 100could be 5 continuous signals and 5 or 4 or 3 or 2 or 1 pulsed signals.In certain forms, the specific drive signal configuration may becontrolled based upon, for example, EEPROM settings in the generator 100and/or user power level selection(s).

In certain forms, a two-position switch may be provided as analternative to a toggle button 137 c. For example, the ultrasonicsurgical instrument 104 may include a toggle button 137 a for producinga continuous output at a maximum power level and a two-position togglebutton 137 b. In a first detented position, toggle button 137 b mayproduce a continuous output at a less than maximum power level, and in asecond detented position the toggle button 137 b may produce a pulsedoutput (e.g., at either a maximum or less than maximum power level,depending upon the EEPROM settings).

In accordance with the described forms, the electrosurgery/RF drivecircuit 116 may generate a drive signal or signals with output powersufficient to perform bipolar electrosurgery using RF energy. In bipolarelectrosurgery applications, the drive signal may be provided, forexample, to electrodes located in the end effector 124 of the RFelectrosurgical instrument 106, for example. Accordingly, the generator100 may be configured for therapeutic purposes by applying electricalenergy to the tissue sufficient for treating the tissue (e.g.,coagulation, cauterization, tissue welding). The generator 100 may beconfigured for sub-therapeutic purposes by applying electrical energy tothe tissue for monitoring parameters of the tissue during a procedure.

As previously discussed, the combination drive circuit 118 may beconfigured to drive both ultrasonic and RF electrosurgical energies. Theultrasonic and RF electrosurgical energies may be delivered thoughseparate output ports of the generator 100 as separate signals or thougha single port of the generator 100 as a single signal that is acombination of the ultrasonic and RF electrosurgical energies. In thelatter case, the single signal can be separated by circuits located inthe surgical instruments 104, 106, 108.

The surgical instruments 104, 106, 108 additionally or alternatively maycomprise a switch to indicate a position of a jaw closure trigger foroperating jaws of the end effector 122, 124, 125. Also, in some forms,the generator 100 may be activated based on the position of the jawclosure trigger, (e.g., as the clinician depresses the jaw closuretrigger to close the jaws, ultrasonic energy may be applied).

The generator 100 may comprise an input device 110 (FIG. 1 ) located,for example, on a front panel of the generator 100 console. The inputdevice 110 may comprise any suitable device that generates signalssuitable for programming the operation of the generator 100. Inoperation, the user can program or otherwise control operation of thegenerator 100 using the input device 110. The input device 110 maycomprise any suitable device that generates signals that can be used bythe generator (e.g., by one or more processors contained in thegenerator) to control the operation of the generator 100 (e.g.,operation of the ultrasonic drive circuit 114, electrosurgery/RF drivecircuit 116, combined RF/ultrasonic drive circuit 118). In variousforms, the input device 110 includes one or more of buttons, switches,thumbwheels, keyboard, keypad, touch screen monitor, pointing device,remote connection to a general purpose or dedicated computer. In otherforms, the input device 110 may comprise a suitable user interface, suchas one or more user interface screens displayed on a touch screenmonitor, for example. Accordingly, by way of the input device 110, theuser can set or program various operating parameters of the generator,such as, for example, current (I), voltage (V), frequency (f), and/orperiod (T) of a drive signal or signals generated by the ultrasonicdrive circuit 114 and/or electrosurgery/RF drive circuit 116.

The generator 100 also may comprise an output device 112 (FIG. 1 ), suchas an output indicator, located, for example, on a front panel of thegenerator 100 console. The output device 112 includes one or moredevices for providing a sensory feedback to a user. Such devices maycomprise, for example, visual feedback devices (e.g., a visual feedbackdevice may comprise incandescent lamps, LEDs, graphical user interface,display, analog indicator, digital indicator, bar graph display, digitalalphanumeric display, liquid crystal display (LCD) screen, lightemitting diode (LED) indicators), audio feedback devices (e.g., an audiofeedback device may comprise speaker, buzzer, audible, computergenerated tone, computerized speech, voice user interface (VUI) tointeract with computers through a voice/speech platform), or tactilefeedback devices (e.g., a tactile feedback device comprises any type ofvibratory feedback, haptic actuator).

Although certain modules and/or blocks of the generator 100 may bedescribed by way of example, it can be appreciated that a greater orlesser number of modules and/or blocks may be used and still fall withinthe scope of the forms. Further, although various forms may be describedin terms of modules and/or blocks to facilitate description, suchmodules and/or blocks may be implemented by one or more hardwarecomponents, e.g., processors, Digital Signal Processors (DSPs),Programmable Logic Devices (PLDs), Application Specific IntegratedCircuits (ASICs), circuits, registers and/or software components, e.g.,programs, subroutines, logic and/or combinations of hardware andsoftware components. Also, in some forms, the various modules describedherein may be implemented utilizing similar hardware positioned withinthe surgical instruments 104, 106, 108 (i.e., the external generator 100may be omitted).

In one form, the ultrasonic drive circuit 114, electrosurgery/RF drivecircuit 116, and/or the combination drive circuit 118 may comprise oneor more embedded applications implemented as firmware, software,hardware, or any combination thereof. The drive circuits 114, 116, 118may comprise various executable modules such as software, programs,data, drivers, application program interfaces (APIs), and so forth. Thefirmware may be stored in nonvolatile memory (NVM), such as in bitmasked read-only memory (ROM) or flash memory. In variousimplementations, storing the firmware in ROM may preserve flash memory.The NVM may comprise other types of memory including, for example,programmable ROM (PROM), erasable programmable ROM (EPROM), EEPROM, orbattery backed random-access memory (RAM) such as dynamic RAM (DRAM),Double-Data-Rate DRAM (DDRAM), and/or synchronous DRAM (SDRAM).

In one form, the drive circuits 114, 116, 118 comprise a hardwarecomponent implemented as a processor for executing program instructionsfor monitoring various measurable characteristics of the surgicalinstruments 104, 106, 108 and generating a corresponding output controlsignals for operating the surgical instruments 104, 106, 108. In formsin which the generator 100 is used in conjunction with the multifunctionsurgical instrument 108, the output control signal may drive theultrasonic transducer 120 in cutting and/or coagulation operating modes.Electrical characteristics of the multifunction surgical instrument 108and/or tissue may be measured and used to control operational aspects ofthe generator 100 and/or provided as feedback to the user. In forms inwhich the generator 100 is used in conjunction with the multifunctionsurgical instrument 108, the output control signal may supply electricalenergy (e.g., RF energy) to the end effector 125 in cutting, coagulationand/or desiccation modes. Electrical characteristics of themultifunction surgical instrument 108 and/or tissue may be measured andused to control operational aspects of the generator 100 and/or providefeedback to the user. In various forms, as previously discussed, thehardware component may be implemented as a DSP, PLD, ASIC, circuits,and/or registers. In one form, the processor may be configured to storeand execute computer software program instructions to generate theoutput signals for driving various components of the surgicalinstruments 104, 106, 108, such as the ultrasonic transducer 120 and theend effectors 122, 124, 125.

FIG. 4 illustrates an equivalent circuit 150 of an ultrasonictransducer, such as the ultrasonic transducer 120, according to oneform. The equivalent circuit 150 comprises a first “motional” branchhaving a serially connected inductance L_(s), resistance R_(s) andcapacitance C_(s) that define the electromechanical properties of theresonator, and a second capacitive branch having a static capacitanceC_(o). Drive current I_(g) may be received from a generator at a drivevoltage V_(g), with motional current I_(m) flowing through the firstbranch and current I_(g)-I_(m) flowing through the capacitive branch.Control of the electromechanical properties of the ultrasonic transducermay be achieved by suitably controlling I_(g) and V_(g). As explainedabove, conventional generator architectures may include a tuninginductor L_(t) (shown in phantom in FIG. 4 ) for tuning out in aparallel resonance circuit the static capacitance Co at a resonantfrequency so that substantially all of generator's current output I_(g)flows through the motional branch. In this way, control of the motionalbranch current I_(m) is achieved by controlling the generator currentoutput I_(g). The tuning inductor L_(t) is specific to the staticcapacitance C_(o) of an ultrasonic transducer, however, and a differentultrasonic transducer having a different static capacitance requires adifferent tuning inductor L_(t). Moreover, because the tuning inductorL_(t) is matched to the nominal value of the static capacitance Co at asingle resonant frequency, accurate control of the motional branchcurrent I_(m) is assured only at that frequency, and as frequency shiftsdown with transducer temperature, accurate control of the motionalbranch current is compromised.

Forms of the generator 100 do not rely on a tuning inductor L_(t) tomonitor the motional branch current 6. Instead, the generator 100 mayuse the measured value of the static capacitance C_(o) in betweenapplications of power for a specific ultrasonic surgical instrument 104(along with drive signal voltage and current feedback data) to determinevalues of the motional branch current I_(m) on a dynamic and ongoingbasis (e.g., in real-time). Such forms of the generator 100 aretherefore able to provide virtual tuning to simulate a system that istuned or resonant with any value of static capacitance C_(o) at anyfrequency, and not just at single resonant frequency dictated by anominal value of the static capacitance C_(o).

FIG. 5 is a simplified block diagram of a generator 200, which is oneform of the generator 100 (FIGS. 1-3 ). The generator 200 is configuredto provide inductorless tuning as described above, among other benefits.Additional details of the generator 200 are described in commonlyassigned and contemporaneously filed U.S. Pat. No. 9,060,775, titledSURGICAL GENERATOR FOR ULTRASONIC AND ELECTROSURGICAL DEVICES, thedisclosure of which is incorporated herein by reference in its entirety.With reference to FIG. 5 , the generator 200 may comprise a patientisolated stage 202 in communication with a non-isolated stage 204 via apower transformer 206. A secondary winding 208 of the power transformer206 is contained in the isolated stage 202 and may comprise a tappedconfiguration (e.g., a center-tapped or a non-center-tappedconfiguration) to define drive signal outputs 210 a, 210 b, 210 c fordelivering drive signals to different surgical instruments, such as, forexample, an ultrasonic surgical instrument 104, an RF electrosurgicalinstrument 106, and a multifunction surgical instrument 108. Inparticular, drive signal outputs 210 a, 210 c may output an ultrasonicdrive signal (e.g., a 420V RMS drive signal) to an ultrasonic surgicalinstrument 104, and drive signal outputs 210 b, 210 c may output anelectrosurgical drive signal (e.g., a 100V RMS drive signal) to an RFelectrosurgical instrument 106, with the drive signal output 2160 bcorresponding to the center tap of the power transformer 206.

In certain forms, the ultrasonic and electrosurgical drive signals maybe provided simultaneously to distinct surgical instruments and/or to asingle surgical instrument having the capability to deliver bothultrasonic and electrosurgical energy to tissue, such as themultifunction surgical instrument 108 (FIGS. 1-3 ). It will beappreciated that the electrosurgical signal, provided either to adedicated electrosurgical instrument and/or to a combined multifunctionultrasonic/electrosurgical instrument may be either a therapeutic orsub-therapeutic level signal where the sub-therapeutic signal can beused, for example, to monitor tissue or instrument conditions andprovide feedback to the generator. For example, the ultrasonic and RFsignals can be delivered separately or simultaneously from a generatorwith a single output port in order to provide the desired output signalto the surgical instrument, as will be discussed in more detail below.Accordingly, the generator can combine the ultrasonic andelectrosurgical RF energies and deliver the combined energies to themultifunction ultrasonic/electrosurgical instrument. Bipolar electrodescan be placed on one or both jaws of the end effector. One jaw may bedriven by ultrasonic energy in addition to electrosurgical RF energy,working simultaneously. The ultrasonic energy may be employed to dissecttissue while the electrosurgical RF energy may be employed for vesselsealing.

The non-isolated stage 204 may comprise a power amplifier 212 having anoutput connected to a primary winding 214 of the power transformer 206.In certain forms the power amplifier 212 may be comprise a push-pullamplifier. For example, the non-isolated stage 204 may further comprisea logic device 216 for supplying a digital output to a DAC circuit 218,which in turn supplies a corresponding analog signal to an input of thepower amplifier 212. In certain forms the logic device 216 may comprisea programmable gate array (PGA), a FPGA, programmable logic device(PLD), among other logic circuits, for example. The logic device 216, byvirtue of controlling the input of the power amplifier 212 via the DACcircuit 218, may therefore control any of a number of parameters (e.g.,frequency, waveform shape, waveform amplitude) of drive signalsappearing at the drive signal outputs 210 a, 210 b, 210 c. In certainforms and as discussed below, the logic device 216, in conjunction witha processor (e.g., a digital signal processor discussed below), mayimplement a number of digital signal processing (DSP)-based and/or othercontrol algorithms to control parameters of the drive signals output bythe generator 200.

Power may be supplied to a power rail of the power amplifier 212 by aswitch-mode regulator 220, e.g., power converter. In certain forms theswitch-mode regulator 220 may comprise an adjustable buck regulator, forexample. The non-isolated stage 204 may further comprise a firstprocessor 222, which in one form may comprise a DSP processor such as anAnalog Devices ADSP-21469 SHARC DSP, available from Analog Devices,Norwood, MA, for example, although in various forms any suitableprocessor may be employed. In certain forms the DSP processor 222 maycontrol operation of the switch-mode regulator 220 responsive to voltagefeedback data received from the power amplifier 212 by the DSP processor222 via an analog-to-digital converter (ADC) circuit 224. In one form,for example, the DSP processor 222 may receive as input, via the ADCcircuit 224, the waveform envelope of a signal (e.g., an RF signal)being amplified by the power amplifier 212. The DSP processor 222 maythen control the switch-mode regulator 220 (e.g., via a pulse-widthmodulated (PWM) output) such that the rail voltage supplied to the poweramplifier 212 tracks the waveform envelope of the amplified signal. Bydynamically modulating the rail voltage of the power amplifier 212 basedon the waveform envelope, the efficiency of the power amplifier 212 maybe significantly improved relative to a fixed rail voltage amplifierschemes.

In certain forms, the logic device 216, in conjunction with the DSPprocessor 222, may implement a digital synthesis circuit such as a DDS(see e.g., FIGS. 13, 14 ) control scheme to control the waveform shape,frequency and/or amplitude of drive signals output by the generator 200.In one form, for example, the logic device 216 may implement a DDScontrol algorithm by recalling waveform samples stored in adynamically-updated lookup table (LUT), such as a RAM LUT, which may beembedded in an FPGA. This control algorithm is particularly useful forultrasonic applications in which an ultrasonic transducer, such as theultrasonic transducer 120, may be driven by a clean sinusoidal currentat its resonant frequency. Because other frequencies may exciteparasitic resonances, minimizing or reducing the total distortion of themotional branch current may correspondingly minimize or reduceundesirable resonance effects. Because the waveform shape of a drivesignal output by the generator 200 is impacted by various sources ofdistortion present in the output drive circuit (e.g., the powertransformer 206, the power amplifier 212), voltage and current feedbackdata based on the drive signal may be input into an algorithm, such asan error control algorithm implemented by the DSP processor 222, whichcompensates for distortion by suitably pre-distorting or modifying thewaveform samples stored in the LUT on a dynamic, ongoing basis (e.g., inreal-time). In one form, the amount or degree of pre-distortion appliedto the LUT samples may be based on the error between a computed motionalbranch current and a desired current waveform shape, with the errorbeing determined on a sample-by-sample basis. In this way, thepre-distorted LUT samples, when processed through the drive circuit, mayresult in a motional branch drive signal having the desired waveformshape (e.g., sinusoidal) for optimally driving the ultrasonictransducer. In such forms, the LUT waveform samples will therefore notrepresent the desired waveform shape of the drive signal, but rather thewaveform shape that is required to ultimately produce the desiredwaveform shape of the motional branch drive signal when distortioneffects are taken into account.

The non-isolated stage 204 may further comprise a first ADC circuit 226and a second ADC circuit 228 coupled to the output of the powertransformer 206 via respective isolation transformers 230, 232 forrespectively sampling the voltage and current of drive signals output bythe generator 200. In certain forms, the ADC circuits 226, 228 may beconfigured to sample at high speeds (e.g., 80 mega samples per second[MSPS]) to enable oversampling of the drive signals. In one form, forexample, the sampling speed of the ADC circuits 226, 228 may enableapproximately 200× (depending on frequency) oversampling of the drivesignals. In certain forms, the sampling operations of the ADC circuit226, 228 may be performed by a single ADC circuit receiving inputvoltage and current signals via a two-way multiplexer. The use ofhigh-speed sampling in forms of the generator 200 may enable, amongother things, calculation of the complex current flowing through themotional branch (which may be used in certain forms to implementDDS-based waveform shape control described above), accurate digitalfiltering of the sampled signals, and calculation of real powerconsumption with a high degree of precision. Voltage and currentfeedback data output by the ADC circuits 226, 228 may be received andprocessed (e.g., first-in-first-out [FIFO] buffer, multiplexer, etc.) bythe logic device 216 and stored in data memory for subsequent retrievalby, for example, the DSP processor 222. As noted above, voltage andcurrent feedback data may be used as input to an algorithm forpre-distorting or modifying LUT waveform samples on a dynamic andongoing basis. In certain forms, this may require each stored voltageand current feedback data pair to be indexed based on, or otherwiseassociated with, a corresponding LUT sample that was output by the logicdevice 216 when the voltage and current feedback data pair was acquired.Synchronization of the LUT samples and the voltage and current feedbackdata in this manner contributes to the correct timing and stability ofthe pre-distortion algorithm.

In certain forms, the voltage and current feedback data may be used tocontrol the frequency and/or amplitude (e.g., current amplitude) of thedrive signals. In one form, for example, voltage and current feedbackdata may be used to determine impedance phase. The frequency of thedrive signal may then be controlled to minimize or reduce the differencebetween the determined impedance phase and an impedance phase setpoint(e.g., 0°), thereby minimizing or reducing the effects of harmonicdistortion and correspondingly enhancing impedance phase measurementaccuracy. The determination of phase impedance and a frequency controlsignal may be implemented in the DSP processor 222, for example, withthe frequency control signal being supplied as input to a DDS controlalgorithm implemented by the logic device 216.

In another form, for example, the current feedback data may be monitoredin order to maintain the current amplitude of the drive signal at acurrent amplitude setpoint. The current amplitude setpoint may bespecified directly or determined indirectly based on specified voltageamplitude and power setpoints. In certain forms, control of the currentamplitude may be implemented by control algorithm, such as, for example,a proportional-integral-derivative (PID) control algorithm, in the DSPprocessor 222. Variables controlled by the control algorithm to suitablycontrol the current amplitude of the drive signal may include, forexample, the scaling of the LUT waveform samples stored in the logicdevice 216 and/or the full-scale output voltage of the DAC circuit 218(which supplies the input to the power amplifier 212) via a DAC circuit234.

The non-isolated stage 204 may further comprise a second processor 236for providing, among other things user interface (UI) functionality. Inone form, the UI processor 236 may comprise an Atmel AT91SAM9263processor having an ARM 926EJ-S core, available from Atmel Corporation,San Jose, CA, for example. Examples of UI functionality supported by theUI processor 236 may include audible and visual user feedback,communication with peripheral devices (e.g., via a Universal Serial Bus[USB] interface), communication with the foot switch 130, communicationwith an input device 110 (e.g., a touch screen display) andcommunication with an output device 112 (e.g., a speaker), as shown inFIGS. 1 and 3 . The UI processor 236 may communicate with the DSPprocessor 222 and the logic device 216 (e.g., via serial peripheralinterface [SPI] buses). Although the UI processor 236 may primarilysupport UI functionality, it may also coordinate with the DSP processor222 to implement hazard mitigation in certain forms. For example, the UIprocessor 236 may be programmed to monitor various aspects of user inputand/or other inputs (e.g., touch screen inputs, foot switch 130 inputsas shown in FIG. 3 , temperature sensor inputs) and may disable thedrive output of the generator 200 when an erroneous condition isdetected.

In certain forms, both the DSP processor 222 and the UI processor 236,for example, may determine and monitor the operating state of thegenerator 200. For the DSP processor 222, the operating state of thegenerator 200 may dictate, for example, which control and/or diagnosticprocesses are implemented by the DSP processor 222. For the UI processor236, the operating state of the generator 200 may dictate, for example,which elements of a user interface (e.g., display screens, sounds) arepresented to a user. The respective DSP and UI processors 222, 236 mayindependently maintain the current operating state of the generator 200and recognize and evaluate possible transitions out of the currentoperating state. The DSP processor 222 may function as the master inthis relationship and determine when transitions between operatingstates are to occur. The UI processor 236 may be aware of validtransitions between operating states and may confirm if a particulartransition is appropriate. For example, when the DSP processor 222instructs the UI processor 236 to transition to a specific state, the UIprocessor 236 may verify that requested transition is valid. In theevent that a requested transition between states is determined to beinvalid by the UI processor 236, the UI processor 236 may cause thegenerator 200 to enter a failure mode.

The non-isolated stage 204 may further comprise a controller 238 formonitoring input devices 110 (e.g., a capacitive touch sensor used forturning the generator 200 on and off, a capacitive touch screen). Incertain forms, the controller 238 may comprise at least one processorand/or other controller device in communication with the UI processor236. In one form, for example, the controller 238 may comprise aprocessor (e.g., a Mega168 8-bit controller available from Atmel)configured to monitor user input provided via one or more capacitivetouch sensors. In one form, the controller 238 may comprise a touchscreen controller (e.g., a QT5480 touch screen controller available fromAtmel) to control and manage the acquisition of touch data from acapacitive touch screen.

In certain forms, when the generator 200 is in a “power off” state, thecontroller 238 may continue to receive operating power (e.g., via a linefrom a power supply of the generator 200, such as the power supply 254discussed below). In this way, the controller 196 may continue tomonitor an input device 110 (e.g., a capacitive touch sensor located ona front panel of the generator 200) for turning the generator 200 on andoff. When the generator 200 is in the power off state, the controller238 may wake the power supply (e.g., enable operation of one or moreDC/DC voltage converters 256 of the power supply 254) if activation ofthe “on/off” input device 110 by a user is detected. The controller 238may therefore initiate a sequence for transitioning the generator 200 toa “power on” state. Conversely, the controller 238 may initiate asequence for transitioning the generator 200 to the power off state ifactivation of the “on/off” input device 110 is detected when thegenerator 200 is in the power on state. In certain forms, for example,the controller 238 may report activation of the “on/off” input device110 to the UI processor 236, which in turn implements the necessaryprocess sequence for transitioning the generator 200 to the power offstate. In such forms, the controller 196 may have no independent abilityfor causing the removal of power from the generator 200 after its poweron state has been established.

In certain forms, the controller 238 may cause the generator 200 toprovide audible or other sensory feedback for alerting the user that apower on or power off sequence has been initiated. Such an alert may beprovided at the beginning of a power on or power off sequence and priorto the commencement of other processes associated with the sequence.

In certain forms, the isolated stage 202 may comprise an instrumentinterface circuit 240 to, for example, provide a communication interfacebetween a control circuit of a surgical instrument (e.g., a controlcircuit comprising handpiece switches) and components of thenon-isolated stage 204, such as, for example, the logic device 216, theDSP processor 222 and/or the UI processor 236. The instrument interfacecircuit 240 may exchange information with components of the non-isolatedstage 204 via a communication link that maintains a suitable degree ofelectrical isolation between the isolated and non-isolated stages 202,204, such as, for example, an infrared (IR)-based communication link.Power may be supplied to the instrument interface circuit 240 using, forexample, a low-dropout voltage regulator powered by an isolationtransformer driven from the non-isolated stage 204.

In one form, the instrument interface circuit 240 may comprise a logiccircuit 242 (e.g., logic circuit, programmable logic circuit, PGA, FPGA,PLD) in communication with a signal conditioning circuit 244. The signalconditioning circuit 244 may be configured to receive a periodic signalfrom the logic circuit 242 (e.g., a 2 kHz square wave) to generate abipolar interrogation signal having an identical frequency. Theinterrogation signal may be generated, for example, using a bipolarcurrent source fed by a differential amplifier. The interrogation signalmay be communicated to a surgical instrument control circuit (e.g., byusing a conductive pair in a cable that connects the generator 200 tothe surgical instrument) and monitored to determine a state orconfiguration of the control circuit. The control circuit may comprise anumber of switches, resistors and/or diodes to modify one or morecharacteristics (e.g., amplitude, rectification) of the interrogationsignal such that a state or configuration of the control circuit isuniquely discernable based on the one or more characteristics. In oneform, for example, the signal conditioning circuit 244 may comprise anADC circuit for generating samples of a voltage signal appearing acrossinputs of the control circuit resulting from passage of interrogationsignal therethrough. The logic circuit 242 (or a component of thenon-isolated stage 204) may then determine the state or configuration ofthe control circuit based on the ADC circuit samples.

In one form, the instrument interface circuit 240 may comprise a firstdata circuit interface 246 to enable information exchange between thelogic circuit 242 (or other element of the instrument interface circuit240) and a first data circuit disposed in or otherwise associated with asurgical instrument. In certain forms, for example, a first data circuit136 (FIG. 2 ) may be disposed in a cable integrally attached to asurgical instrument handpiece, or in an adaptor for interfacing aspecific surgical instrument type or model with the generator 200. Thefirst data circuit 136 may be implemented in any suitable manner and maycommunicate with the generator according to any suitable protocolincluding, for example, as described herein with respect to the firstdata circuit 136. In certain forms, the first data circuit may comprisea non-volatile storage device, such as an EEPROM device. In certainforms and referring again to FIG. 5 , the first data circuit interface246 may be implemented separately from the logic circuit 242 andcomprise suitable circuitry (e.g., discrete logic devices, a processor)to enable communication between the logic circuit 242 and the first datacircuit. In other forms, the first data circuit interface 246 may beintegral with the logic circuit 242.

In certain forms, the first data circuit 136 *FIG. 2 ) may storeinformation pertaining to the particular surgical instrument with whichit is associated. Such information may include, for example, a modelnumber, a serial number, a number of operations in which the surgicalinstrument has been used, and/or any other type of information. Thisinformation may be read by the instrument interface circuit 240 (e.g.,by the logic circuit 242), transferred to a component of thenon-isolated stage 204 (e.g., to logic device 216, DSP processor 222and/or UI processor 236) for presentation to a user via an output device112 (FIGS. 1 and 3 ) and/or for controlling a function or operation ofthe generator 200. Additionally, any type of information may becommunicated to first data circuit 136 for storage therein via the firstdata circuit interface 246 (e.g., using the logic circuit 242). Suchinformation may comprise, for example, an updated number of operationsin which the surgical instrument has been used and/or dates and/or timesof its usage.

As discussed previously, a surgical instrument may be detachable from ahandpiece (e.g., the multifunction surgical instrument 108 may bedetachable from the handpiece 109) to promote instrumentinterchangeability and/or disposability. In such cases, conventionalgenerators may be limited in their ability to recognize particularinstrument configurations being used and to optimize control anddiagnostic processes accordingly. The addition of readable data circuitsto surgical instruments to address this issue is problematic from acompatibility standpoint, however. For example, designing a surgicalinstrument to remain backwardly compatible with generators that lack therequisite data reading functionality may be impractical due to, forexample, differing signal schemes, design complexity, and cost. Forms ofinstruments discussed herein address these concerns by using datacircuits that may be implemented in existing surgical instrumentseconomically and with minimal design changes to preserve compatibilityof the surgical instruments with current generator platforms.

Additionally, forms of the generator 200 may enable communication withinstrument-based data circuits. For example, the generator 200 may beconfigured to communicate with a second data circuit 138 (FIG. 2 )contained in an instrument (e.g., the multifunction surgical instrument108 shown in FIG. 2 ). In some forms, the second data circuit 138 may beimplemented in a many similar to that of the first data circuit 136(FIG. 2 ) described herein. The instrument interface circuit 240 maycomprise a second data circuit interface 248 to enable thiscommunication. In one form, the second data circuit interface 248 maycomprise a tri-state digital interface, although other interfaces mayalso be used. In certain forms, the second data circuit may generally beany circuit for transmitting and/or receiving data. In one form, forexample, the second data circuit may store information pertaining to theparticular surgical instrument with which it is associated. Suchinformation may include, for example, a model number, a serial number, anumber of operations in which the surgical instrument has been used,and/or any other type of information.

In some forms, the second data circuit 138 (FIG. 2 ) may storeinformation about the electrical and/or ultrasonic properties of anassociated ultrasonic transducer 120, end effector 125, or ultrasonicdrive system. For example, the first data circuit 136 (FIG. 2 ) mayindicate a burn-in frequency slope, as described herein. Additionally oralternatively, any type of information may be communicated to seconddata circuit for storage therein via the second data circuit interface248 (e.g., using the logic circuit 242). Such information may comprise,for example, an updated number of operations in which the instrument hasbeen used and/or dates and/or times of its usage. In certain forms, thesecond data circuit may transmit data acquired by one or more sensors(e.g., an instrument-based temperature sensor). In certain forms, thesecond data circuit may receive data from the generator 200 and providean indication to a user (e.g., an LED indication or other visibleindication) based on the received data.

In certain forms, the second data circuit and the second data circuitinterface 248 may be configured such that communication between thelogic circuit 242 and the second data circuit can be effected withoutthe need to provide additional conductors for this purpose (e.g.,dedicated conductors of a cable connecting a handpiece to the generator200). In one form, for example, information may be communicated to andfrom the second data circuit using a 1-wire bus communication schemeimplemented on existing cabling, such as one of the conductors usedtransmit interrogation signals from the signal conditioning circuit 244to a control circuit in a handpiece. In this way, design changes ormodifications to the surgical instrument that might otherwise benecessary are minimized or reduced. Moreover, because different types ofcommunications implemented over a common physical channel can befrequency-band separated, the presence of a second data circuit may be“invisible” to generators that do not have the requisite data readingfunctionality, thus enabling backward compatibility of the surgicalinstrument.

In certain forms, the isolated stage 202 may comprise at least oneblocking capacitor 250-1 connected to the drive signal output 210 b toprevent passage of DC current to a patient. A single blocking capacitormay be required to comply with medical regulations or standards, forexample. While failure in single-capacitor designs is relativelyuncommon, such failure may nonetheless have negative consequences. Inone form, a second blocking capacitor 250-2 may be provided in serieswith the blocking capacitor 250-1, with current leakage from a pointbetween the blocking capacitors 250-1, 250-2 being monitored by, forexample, an ADC circuit 252 for sampling a voltage induced by leakagecurrent. The samples may be received by the logic circuit 242, forexample. Based changes in the leakage current (as indicated by thevoltage samples in the form of FIG. 5 ), the generator 200 may determinewhen at least one of the blocking capacitors 250-1, 250-2 has failed.Accordingly, the form of FIG. 5 provides a benefit over single-capacitordesigns having a single point of failure.

In certain forms, the non-isolated stage 204 may comprise a power supply254 for delivering DC power at a suitable voltage and current. The powersupply may comprise, for example, a 400 W power supply for delivering a48 VDC system voltage. The power supply 254 may further comprise one ormore DC/DC voltage converters 256 for receiving the output of the powersupply to generate DC outputs at the voltages and currents required bythe various components of the generator 200. As discussed above inconnection with the controller 238, one or more of the DC/DC voltageconverters 256 may receive an input from the controller 238 whenactivation of the “on/off” input device 110 by a user is detected by thecontroller 238 to enable operation of, or wake, the DC/DC voltageconverters 256.

FIG. 6 illustrates one form of a drive system 302 of a generator 300,which is one form of the generator 100 (FIGS. 1-3 ). The generator 300is configured to provide an ultrasonic electrical signal for driving anultrasonic transducer (e.g., ultrasonic transducer 120 FIGS. 1-3 ), alsoreferred to as a drive signal. The generator 300 is similar to and maybe interchangeable with the generators 100, 200 (FIGS. 1-3 and 5 ). Thedrive system 302 is flexible and can create an ultrasonic electricaldrive signal 304 at a desired frequency and power level setting fordriving the ultrasonic transducer 306. In various forms, the generator300 may comprise several separate functional elements, such as modulesand/or blocks. Although certain modules and/or blocks may be describedby way of example, it can be appreciated that a greater or lesser numberof modules and/or blocks may be used and still fall within the scope ofthe forms. Further, although various forms may be described in terms ofmodules and/or blocks to facilitate description, such modules and/orblocks may be implemented by one or more hardware components, e.g.,processors, Digital Signal Processors (DSPs), Programmable Logic Devices(PLDs), Application Specific Integrated Circuits (ASICs), circuits,registers and/or software components, e.g., programs, subroutines, logicand/or combinations of hardware and software components.

In one form, the generator 300 drive system 302 may comprise one or moreembedded applications implemented as firmware, software, hardware, orany combination thereof. The generator 300 drive system 302 may comprisevarious executable modules such as software, programs, data, drivers,application program interfaces (APIs), and so forth. The firmware may bestored in nonvolatile memory (NVM), such as in bit-masked read-onlymemory (ROM) or flash memory. In various implementations, storing thefirmware in ROM may preserve flash memory. The NVM may comprise othertypes of memory including, for example, programmable ROM (PROM),erasable programmable ROM (EPROM), EEPROM, or battery backedrandom-access memory (RAM) such as dynamic RAM (DRAM), Double-Data-RateDRAM (DDRAM), and/or synchronous DRAM (SDRAM).

In one form, the generator 300 drive system 302 comprises a hardwarecomponent implemented as a processor 308 for executing programinstructions for monitoring various measurable characteristics of theultrasonic surgical instrument 104 (FIG. 1 ) and generating an outputsignal for driving the ultrasonic transducer in cutting and/orcoagulation operating modes. It will be appreciated by those skilled inthe art that the generator 300 and the drive system 302 may compriseadditional or fewer components and only a simplified version of thegenerator 300 and the drive system 302 are described herein forconciseness and clarity. In various forms, as previously discussed, thehardware component may be implemented as a DSP, PLD, ASIC, circuits,and/or registers. In one form, the processor 308 may be configured tostore and execute computer software program instructions to generate theoutput signals for driving various components of the ultrasonic surgicalinstrument 104, such as a transducer, an end effector, and/or a blade.

In one form, under control of one or more software program routines, theprocessor 308 executes the methods in accordance with the describedforms to generate an electrical signal output waveform comprisingcurrent (I), voltage (V), and/or frequency (f) for various timeintervals or periods (T). The stepwise waveforms of the drive signalsmay be generated by forming a piecewise linear combination of constantfunctions over a plurality of time intervals created by stepping thegenerator 300 drive signals, e.g., output drive current (I), voltage(V), and/or frequency (f). The time intervals or periods (T) may bepredetermined (e.g., fixed and/or programmed by the user) or may bevariable. Variable time intervals may be defined by setting the drivesignal to a first value and maintaining the drive signal at that valueuntil a change is detected in a monitored characteristic. Examples ofmonitored characteristics may comprise, for example, transducerimpedance, tissue impedance, tissue heating, tissue transection, tissuecoagulation, and the like. The ultrasonic drive signals generated by thegenerator 300 include, without limitation, ultrasonic drive signalscapable of exciting the ultrasonic transducer 306 in various vibratorymodes such as, for example, the primary longitudinal mode and harmonicsthereof as well flexural and torsional vibratory modes.

In one form, the executable modules comprise one or more algorithm(s)310 stored in memory that when executed causes the processor 308 togenerate an electrical signal output waveform comprising current (I),voltage (V), and/or frequency (f) for various time intervals or periods(T). The stepwise waveforms of the drive signals may be generated byforming a piecewise linear combination of constant functions over two ormore time intervals created by stepping the output drive current (I),voltage (V), and/or frequency (f) of the generator 300. The drivesignals may be generated either for predetermined fixed time intervalsor periods (T) of time or variable time intervals or periods of time inaccordance with the one or more algorithm(s) 310. Under control of theprocessor 308, the generator 100 outputs (e.g., increases or decreases)the current (I), voltage (V), and/or frequency (f) up or down at aparticular resolution for a predetermined period (T) or until apredetermined condition is detected, such as a change in a monitoredcharacteristic (e.g., transducer impedance, tissue impedance). The stepscan change in programmed increments or decrements. If other steps aredesired, the generator 300 can increase or decrease the step adaptivelybased on measured system characteristics.

In operation, the user can program the operation of the generator 300using the input device 312 located on the front panel of the generator300 console. The input device 312 may comprise any suitable device thatgenerates signals 314 that can be applied to the processor 308 tocontrol the operation of the generator 300. In various forms, the inputdevice 312 includes buttons, switches, thumbwheels, keyboard, keypad,touch screen monitor, pointing device, remote connection to a generalpurpose or dedicated computer. In other forms, the input device 312 maycomprise a suitable user interface. Accordingly, by way of the inputdevice 312, the user can set or program the current (I), voltage (V),frequency (f), and/or period (T) for programming the output of thegenerator 300. The processor 308 then displays the selected power levelby sending a signal on line 316 to an output indicator 318.

In various forms, the output indicator 318 may provide visual, audible,and/or tactile feedback to the surgeon to indicate the status of asurgical procedure, such as, for example, when tissue cutting andcoagulating is complete based on a measured characteristic of theultrasonic surgical instrument 104, e.g., transducer impedance, tissueimpedance, or other measurements as subsequently described. By way ofexample, and not limitation, visual feedback comprises any type ofvisual indication device including incandescent lamps or LEDs, graphicaluser interface, display, analog indicator, digital indicator, bar graphdisplay, digital alphanumeric display. By way of example, and notlimitation, audible feedback comprises any type of buzzer, computergenerated tone, computerized speech, voice user interface (VUI) tointeract with computers through a voice/speech platform. By way ofexample, and not limitation, tactile feedback comprises any type ofvibratory feedback provided through an instrument housing handleassembly.

In one form, the processor 308 may be configured or programmed togenerate a digital current signal 320 and a digital frequency signal322. These digital signals 320, 322 are applied to a digital synthesiscircuit such as the DDS circuit 324 (see e.g., FIGS. 13, 14 ) to adjustthe amplitude and the frequency (f) of the ultrasonic electrical drivesignal 304 to the transducer. The output of the DDS circuit 324 isapplied to a power amplifier 326 whose output is applied to atransformer 328. The output of the transformer 328 is the ultrasonicelectrical drive signal 304 applied to the ultrasonic transducer 306,which is coupled to a blade by way of a waveguide. The output of the DDScircuit 324 may be stored in one more memory circuits including volatile(RAM) and non-volatile (ROM) memory circuits.

In one form, the generator 300 comprises one or more measurement modulesor components that may be configured to monitor measurablecharacteristics of the ultrasonic instrument 104 (FIGS. 1, 2 ) or themultifunction electrosurgical/ultrasonic instrument 108 (FIGS. 1-3 ). Inthe illustrated form, the processor 308 may be employed to monitor andcalculate system characteristics. As shown, the processor 308 measuresthe impedance Z of the transducer by monitoring the current supplied tothe ultrasonic transducer 306 and the voltage applied to the transducer.In one form, a current sense circuit 330 is employed to sense thecurrent flowing through the transducer and a voltage sense circuit 332is employed to sense the output voltage applied to the ultrasonictransducer 306. These signals may be applied to the ADC circuit 336 viaan analog multiplexer 334 circuit or switching circuit arrangement. Theanalog multiplexer 334 routes the appropriate analog signal to the ADCcircuit 336 for conversion. In other forms, multiple ADC circuits 336may be employed for each measured characteristic instead of the analogmultiplexer 334 circuit. The processor 308 receives the digital output338 of the ADC circuit 336 and calculates the transducer impedance Zbased on the measured values of current and voltage. The processor 308adjusts the ultrasonic electrical drive signal 304 such that it cangenerate a desired power versus load curve. In accordance withprogrammed algorithm(s) 310, the processor 308 can step the ultrasonicelectrical drive signal 304, e.g., the current or frequency, in anysuitable increment or decrement in response to the transducer impedanceZ.

FIG. 7 illustrates one aspect of a drive system 402 of the generator400, which is one form of the generator 100 (FIGS. 1-3 ). In operation,the user can program the operation of the generator 400 using the inputdevice 412 located on the front panel of the generator 400 console. Theinput device 412 may comprise any suitable device that generates signals414 that can be applied to the processor 408 to control the operation ofthe generator 400. In various forms, the input device 412 includesbuttons, switches, thumbwheels, keyboard, keypad, touch screen monitor,pointing device, remote connection to a general purpose or dedicatedcomputer. In other forms, the input device 412 may comprise a suitableuser interface. Accordingly, by way of the input device 412, the usercan set or program the current (I), voltage (V), frequency (f), and/orperiod (T) for programming the output of the generator 400. Theprocessor 408 then displays the selected power level by sending a signalon line 416 to an output indicator 418.

The generator 400 comprises a tissue impedance module 442. The drivesystem 402 is configured to generate electrical drive signal 404 todrive the ultrasonic transducer 406. In one aspect, the tissue impedancemodule 442 may be configured to measure the impedance Zt of tissuegrasped between the blade 440 and the clamp arm assembly 444. The tissueimpedance module 442 comprises an RF oscillator 446, an RF voltagesensing circuit 448, and an RF current sensing circuit 450. The RFvoltage and RF current sensing circuits 448, 450 respond to the RFvoltage Vrf applied to the blade 440 electrode and the RF current Irfflowing through the blade 440 electrode, the tissue, and the conductiveportion of the clamp arm assembly 444. The sensed voltage Vrf andcurrent Irf are converted to digital form by the ADC circuit 436 via theanalog multiplexer 434. The processor 408 receives the digital output438 of the ADC circuit 436 and determines the tissue impedance Zt bycalculating the ratio of the RF voltage Vrf to current Irf measured bythe RF voltage sense circuit 448 and the RF current sense circuit 450.In one aspect, the transection of the inner muscle layer and the tissuemay be detected by sensing the tissue impedance Zt. Accordingly,detection of the tissue impedance Zt may be integrated with an automatedprocess for separating the inner muscle layer from the outer adventitialayer prior to transecting the tissue without causing a significantamount of heating, which normally occurs at resonance.

In one form, the RF voltage Vrf applied to the blade 440 electrode andthe RF current Irf flowing through the blade 440 electrode, the tissue,and the conductive portion of the clamp arm assembly 451 are suitablefor vessel sealing and/or dissecting. Thus, the RF power output of thegenerator 400 can be selected for non-therapeutic functions such astissue impedance measurements as well as therapeutic functions such asvessel sealing and/or dissection. It will be appreciated, that in thecontext of the present disclosure, the ultrasonic and the RFelectrosurgical energies can be supplied by the generator eitherindividually or simultaneously.

In various forms, feedback is provided by the output indicator 418 shownin FIGS. 6 and 7 . The output indicator 418 is particularly useful inapplications where the tissue being manipulated by the end effector isout of the user's field of view and the user cannot see when a change ofstate occurs in the tissue. The output indicator 418 communicates to theuser that a change in tissue state has occurred. As previouslydiscussed, the output indicator 418 may be configured to provide varioustypes of feedback to the user including, without limitation, visual,audible, and/or tactile feedback to indicate to the user (e.g., surgeon,clinician) that the tissue has undergone a change of state or conditionof the tissue. By way of example, and not limitation, as previouslydiscussed, visual feedback comprises any type of visual indicationdevice including incandescent lamps or LEDs, graphical user interface,display, analog indicator, digital indicator, bar graph display, digitalalphanumeric display. By way of example, and not limitation, audiblefeedback comprises any type of buzzer, computer generated tone,computerized speech, VUI to interact with computers through avoice/speech platform. By way of example, and not limitation, tactilefeedback comprises any type of vibratory feedback provided through theinstrument housing handle assembly. The change of state of the tissuemay be determined based on transducer and tissue impedance measurementsas previously described, or based on voltage, current, and frequencymeasurements.

In one form, the processor 408 may be configured or programmed togenerate a digital current signal 420 and a digital frequency signal422. These digital signals 420, 422 are applied to a digital synthesiscircuit such as the DDS circuit 424 (see e.g., FIGS. 13, 14 ) to adjustthe amplitude and the frequency (f) of the electrical drive signal 404to the transducer 406. The output of the DDS circuit 424 is applied to apower amplifier 426 whose output is applied to a transformer 428. Theoutput of the transformer 428 is the electrical drive signal 404 appliedto the ultrasonic transducer 406, which is coupled to a blade by way ofa waveguide. The output of the DDS circuit 424 may be stored in one morememory circuits including volatile (RAM) and non-volatile (ROM) memorycircuits.

In one form, the generator 400 comprises one or more measurement modulesor components that may be configured to monitor measurablecharacteristics of the ultrasonic instrument 104 (FIGS. 1, 3 ) or themultifunction electrosurgical/ultrasonic instrument 108 (FIGS. 1-3 ). Inthe illustrated form, the processor 408 may be employed to monitor andcalculate system characteristics. As shown, the processor 408 measuresthe impedance Z of the transducer by monitoring the current supplied tothe ultrasonic transducer 406 and the voltage applied to the transducer.In one form, a current sense circuit 430 is employed to sense thecurrent flowing through the transducer and a voltage sense circuit 432is employed to sense the output voltage applied to the ultrasonictransducer 406. These signals may be applied to the ADC circuit 436 viaan analog multiplexer 434 circuit or switching circuit arrangement. Theanalog multiplexer 434 routes the appropriate analog signal to the ADCcircuit 436 for conversion. In other forms, multiple ADC circuits 436may be employed for each measured characteristic instead of the analogmultiplexer 434 circuit. The processor 408 receives the digital output438 of the ADC circuit 436 and calculates the transducer impedance Zbased on the measured values of current and voltage. The processor 308adjusts the electrical drive signal 404 such that it can generate adesired power versus load curve. In accordance with programmedalgorithm(s) 410, the processor 408 can step the ultrasonic electricaldrive signal 404, e.g., the current or frequency, in any suitableincrement or decrement in response to the transducer impedance Z.

With reference to FIGS. 6 and 7 , in various forms, the variousexecutable instructions or modules (e.g., algorithms 310, 410)comprising computer readable instructions can be executed by theprocessor 308, 408 portion of the generator 300, 400. In various forms,the operations described with respect to the algorithms may beimplemented as one or more software components, e.g., programs,subroutines, logic; one or more hardware components, e.g., processors,DSPs, PLDs, ASICs, circuits, registers; and/or combinations of softwareand hardware. In one form, the executable instructions to perform thealgorithms may be stored in memory. When executed, the instructionscause the processor 308, 408 to determine a change in tissue stateprovide feedback to the user by way of the output indicator 318, 418. Inaccordance with such executable instructions, the processor 308, 408monitors and evaluates the voltage, current, and/or frequency signalsamples available from the generator 300, 400 and according to theevaluation of such signal samples determines whether a change in tissuestate has occurred. As further described below, a change in tissue statemay be determined based on the type of ultrasonic instrument and thepower level that the instrument is energized at. In response to thefeedback, the operational mode of the surgical instruments 104, 106, 108(FIGS. 1-3 ) may be controlled by the user or may be automatically orsemi-automatically controlled.

FIG. 8 illustrates an example of a generator 500, which is one form ofthe generator 100 (FIGS. 1-3 ). The generator 500 is configured todeliver multiple energy modalities to a surgical instrument. Thegenerator 500 includes functionalities of the generators 200, 300, 400shown in FIGS. 5-7 . The generator 500 provides RF and ultrasonicsignals for delivering energy to a surgical instrument. The RF andultrasonic signals may be provided alone or in combination and may beprovided simultaneously. As noted above, at least one generator outputcan deliver multiple energy modalities (e.g., ultrasonic, bipolar ormonopolar RF, irreversible and/or reversible electroporation, and/ormicrowave energy, among others) through a single port and these signalscan be delivered separately or simultaneously to the end effector totreat tissue. The generator 500 comprises a processor 502 coupled to awaveform generator 504. The processor 502 and waveform generator 504 areconfigured to generate a variety of signal waveforms based oninformation stored in a memory coupled to the processor 502, not shownfor clarity of disclosure. The digital information associated with awaveform is provided to the waveform generator 504 which includes one ormore DAC circuits to convert the digital input into an analog output.The analog output is fed to an amplifier 1106 for signal conditioningand amplification. The conditioned and amplified output of the amplifier506 is coupled to a power transformer 508. The signals are coupledacross the power transformer 508 to the secondary side, which is in thepatient isolation side. A first signal of a first energy modality isprovided to the surgical instrument between the terminals labeledENERGY1 and RETURN. A second signal of a second energy modality iscoupled across a capacitor 510 and is provided to the surgicalinstrument between the terminals labeled ENERGY2 and RETURN. It will beappreciated that more than two energy modalities may be output and thusthe subscript “n” may be used to designate that up to n ENERGYnterminals may be provided, where n is a positive integer greater than 1.It also will be appreciated that up to “n” return paths RETURNn may beprovided without departing from the scope of the present disclosure.

A first voltage sensing circuit 512 is coupled across the terminalslabeled ENERGY1 and the RETURN path to measure the output voltagetherebetween. A second voltage sensing circuit 524 is coupled across theterminals labeled ENERGY2 and the RETURN path to measure the outputvoltage therebetween. A current sensing circuit 514 is disposed inseries with the RETURN leg of the secondary side of the powertransformer 508 as shown to measure the output current for either energymodality. If different return paths are provided for each energymodality, then a separate current sensing circuit should be provided ineach return leg. The outputs of the first and second voltage sensingcircuits 512, 524 are provided to respective isolation transformers 516,522 and the output of the current sensing circuit 514 is provided toanother isolation transformer 518. The outputs of the isolationtransformers 516, 518, 522 in the on the primary side of the powertransformer 508 (non-patient-isolated side) are provided to a one ormore ADC circuit 526. The digitized output of the ADC circuit 526 isprovided to the processor 502 for further processing and computation.The output voltages and output current feedback information can beemployed to adjust the output voltage and current provided to thesurgical instrument and to compute output impedance, among otherparameters. Input/output communications between the processor 502 andpatient isolated circuits is provided through an interface circuit 520.Sensors also may be in electrical communication with the processor 502by way of the interface circuit 520.

In one aspect, the impedance may be determined by the processor 502 bydividing the output of either the first voltage sensing circuit 512coupled across the terminals labeled ENERGY1/RETURN or the secondvoltage sensing circuit 524 coupled across the terminals labeledENERGY2/RETURN by the output of the current sensing circuit 514 disposedin series with the RETURN leg of the secondary side of the powertransformer 508. The outputs of the first and second voltage sensingcircuits 512, 524 are provided to separate isolations transformers 516,522 and the output of the current sensing circuit 514 is provided toanother isolation transformer 516. The digitized voltage and currentsensing measurements from the ADC circuit 526 are provided the processor502 for computing impedance. As an example, the first energy modalityENERGY1 may be ultrasonic energy and the second energy modality ENERGY2may be RF energy. Nevertheless, in addition to ultrasonic and bipolar ormonopolar RF energy modalities, other energy modalities includeirreversible and/or reversible electroporation and/or microwave energy,among others. Also, although the example illustrated in FIG. 8 shows asingle return path RETURN may be provided for two or more energymodalities, in other aspects multiple return paths RETURNn may beprovided for each energy modality ENERGYn. Thus, as described herein,the ultrasonic transducer impedance may be measured by dividing theoutput of the first voltage sensing circuit 512 by the current sensingcircuit 514 and the tissue impedance may be measured by dividing theoutput of the second voltage sensing circuit 524 by the current sensingcircuit 514.

As shown in FIG. 8 , the generator 500 comprising at least one outputport can include a power transformer 508 with a single output and withmultiple taps to provide power in the form of one or more energymodalities, such as ultrasonic, bipolar or monopolar RF, irreversibleand/or reversible electroporation, and/or microwave energy, amongothers, for example, to the end effector depending on the type oftreatment of tissue being performed. For example, the generator 500 candeliver energy with higher voltage and lower current to drive anultrasonic transducer, with lower voltage and higher current to drive RFelectrodes for sealing tissue, or with a coagulation waveform for spotcoagulation using either monopolar or bipolar RF electrosurgicalelectrodes. The output waveform from the generator 500 can be steered,switched, or filtered to provide the frequency to the end effector ofthe surgical instrument. The connection of an ultrasonic transducer tothe generator 500 output would be preferably located between the outputlabeled ENERGY1 and RETURN as shown in FIG. 8 . An In one example, aconnection of RF bipolar electrodes to the generator 500 output would bepreferably located between the output labeled ENERGY2 and RETURN. In thecase of monopolar output, the preferred connections would be activeelectrode (e.g., pencil or other probe) to the ENERGY2 output and asuitable return pad connected to the RETURN output.

In other aspects, the generators 100, 200, 300, 400, 500 described inconnection with FIGS. 1-3 and 5-8 , the ultrasonic drive circuit 114,and/or electrosurgery/RF drive circuit 116 as described in connectionwith FIG. 3 may be formed integrally with any one of the surgicalinstruments 104, 106, 108 described in connection with FIGS. 1 and 2 .Accordingly, any of the processors, digital signal processors, circuits,controllers, logic devices, ADCs, DACs, amplifiers, converters,transformers, signal conditioners, data interface circuits, current andvoltage sensing circuits, direct digital synthesis circuits, multiplexer(analog or digital), waveform generators, RF generators, memory, and thelike, described in connection with any one of the generators 100, 200,300, 400, 500 can be located within the surgical instruments 104, 106,108 or may be located remotely from the surgical instruments 104, 106,108 and coupled to the surgical instruments via wired and/or wirelesselectrical connections.

FIG. 9 shows a diagram of an electrosurgical system 9000 that allows fortwo ports on a generator 9001 and accounts for electrical isolationbetween two surgical instruments 9007, 9008. A scheme is provided forelectrical isolation between the two surgical instruments 9007, 9008 asthey are located on the same patient isolation circuit. According to theconfiguration shown in FIG. 9 , unintended electrical power feedback isprevented through the electrosurgical system 9000. In various aspects,power field-effect-transistors (FETs) or relays are used to electricallyisolate all power lines for each instrument 9007, 9008. According to oneaspect, the power FETs or relays are controlled by a 1-wirecommunication protocol.

As shown in FIG. 9 , a generator 9001, which is one form of thegenerator 100 (FIGS. 1-3 ), is coupled to a power switching mechanism9003 and a communications system 9005. In one aspect, the powerswitching mechanism 9003 comprises power FETs, such as power metal-oxidesemiconductor FETs (MOSFETs), and/or relays, such as electromechanicalrelays. In one aspect, the communications system 9005 comprisescomponents for D1 emulation, FPGA expansion, and time slicingfunctionalities. The power switching mechanism 9003 is coupled to thecommunications system 9005. Each of the power switching mechanism 9003and the communications system 9005 are coupled to surgical instruments9007, 9009 (labeled device 1 and device 2). Each of surgical instruments9007, 9009 comprise components for a combined RF and Ultrasonic energyinput 9011, hand switch (HSVV) 1-wire serial protocol interface 9013, HP1-wire serial protocol interface 9015, and a presence interface 9017.The power switching mechanism 9003 is coupled to the RF and Ultrasonicenergy input 9011 for each of surgical instruments 9007, 9008. Thecommunications system 9005 is coupled to the HSW 1-wire serial protocolinterface 9013, 9014, the HP 1-wire serial protocol interface 9015,9016, and presence interface 9017, 9018 for each of surgical instruments9007, 9008. While two surgical instruments are shown in FIG. 9 , theremay be more than two devices according to various aspects.

FIGS. 10-12 illustrate aspects of an interface with a generator tosupport two instruments simultaneously that allows the instruments toquickly switch between active/inactive by a user in a sterile field.FIGS. 10-12 describe multiple communication schemes which would allowfor a super cap/battery charger and dual surgical instruments. Theaspects of FIGS. 10-12 allow for communications to two surgicalinstruments in the surgical field from a generator with at least onecommunications port and allow for an operator in sterile field to switchbetween devices, for example, without modifying the surgicalinstruments.

FIG. 10 is a diagram of a communications architecture of system 1001comprising a generator 1003, which is one form of the generator 100(FIGS. 1-3 ), and surgical instruments 9007, 9008, which are shown inFIG. 9 . According to FIG. 10 , the generator 9001 is configured fordelivering multiple energy modalities to a plurality of surgicalinstruments. As discussed herein the various energy modalities include,without limitation, ultrasonic, bipolar or monopolar RF, reversibleand/or irreversible electroporation, and/or microwave energy modalities.The generator 9001 comprises a combined energy modalities power output1005, a communications interface 1007, and a presence interface 1049.According to the aspect of FIG. 10 , the communications interface 1007comprises an HSW serial interface 1011 and an HP serial interface 1013.The serial interfaces 1011, 1013 may comprise inter-integrated circuit(I²C), half duplex serial peripheral interface (SPI), and/or UniversalAsynchronous Receiver Transmitter (UART) components and/orfunctionalities. The generator 1003 provides the combined energymodalities power output 1005 to an adapter 1015, for example, apass-through charger (PTC). The adapter 1015 comprises energy storagecircuit 1071, control circuit 1019, a unique presence element 1021, andassociated circuit discussed below. In one aspect, the presence element1021 is a resistor. In another aspect, the presence element 1021 may bea bar code, Quick Response (QR) code, or similar code, or a value storedin memory such as, for example, a value stored in NVM. The presenceelement 1021 may be unique to the adapter 1015 so that, in the eventthat another adapter that did not use the same wire interfaces could notbe used with the unique presence element 1021. In one aspect, the uniquepresence element 1021 is a resistor. The energy storage circuit 1071comprises a switching mechanism 1023, energy storage device 1025,storage control 1027, storage monitoring component 1029, and a devicepower monitoring component 1031. The control circuit 1019 may comprise aprocessor, FPGA, PLD, complex programmable logic device (CPLD),microcontroller, DSP, and/or ASIC, for example. According to the aspectshown in FIG. 10 , an FPGA or microcontroller would act as an extensionof an existing, similar computing hardware and allows for information tobe relayed from on entity to another entity.

The switching mechanism 1023 is configured to receive the combinedenergy modalities power output 1005 from the generator 1003 and it maybe provided to the energy storage device 1025, surgical instrument 9007,and/or surgical instrument 9008. The device power monitoring component1031 is coupled to the channels for the energy storage device 1025,surgical instrument 9007, surgical instrument 9008, and may monitorwhere power is flowing. The control circuit 1019 comprises communicationinterface 1033 coupled to the HSW serial interface 1011 and an HP serialinterface 1013 of the generator 1003. The control circuit 1019 is alsocoupled to the storage control 1027, storage monitoring component 1029,and device power monitoring component 1031 of the energy storage circuit1071.

The control circuit 1019 further comprises a serial master interface1035 that is coupled to HSW #1 circuit 1037 and HSW #2 circuit 1038,includes generation and ADC circuit, a form of memory (non volatile orflash) 1039, along with a method for detecting the presence of anattached instrument (Presence) #1 circuit 1041 and Presence #2 circuit1042, which includes a voltage or current source and ADC circuit. Theserial master interface 1035 also includes HSW NVM bypass channels,which couple the serial master interface 1035 to the outputs of the HSW#1 circuit 1037 and the HSW #2 circuit 1038, respectively. The HSW #1circuit 1037 and HSW #2 circuit 1038 are coupled to the HSW 1-wireserial protocol interfaces 9013, 9014 of the surgical instruments 9007,9008, respectively. The serial master interface 1035 further includes HPserial channels that are coupled to the HP 1-wire serial protocolinterfaces 9015, 9016 of the surgical instruments 9007, 9008,respectively. Further, Presence #1 and Presence #2 circuits 1041, 1042are coupled to the presence interfaces 9017, 9018 of the surgicalinstruments 9007, 9008, respectively.

The system 1001 allows the control circuit 1019, such as an FPGA, tocommunicate with more surgical instruments using adapter 1015, whichacts as an expansion adapter device. According to various aspects, theadapter 1015 expands the Input/Output (I/O) capability of the generator1003 control. The adapter 1015 may function as an extension of thecentral processing unit that allows commands to be transmitted over abus between the adapter 1015 and the generator 1003 and unpacks thecommands and use them to bit-bang over interfaces or to controlconnected analog circuit. The adapter 1015 also allows for reading inADC values from connected surgical instruments 9007, 9008 and relay thisinformation to the generator control and the generator control wouldthen control the two surgical instruments 9007, 9008. According tovarious aspects, the generator 1003 may control the surgical instruments9007, 9008 as two separate state machines and may store the data.

Existing interfaces (the HSW serial interface 1011 and the HP serialinterface 1013 lines from generator 1003) may be used in a two-wirecommunication protocol that enables the generator 1003 control tocommunicate with multiple surgical instruments connected to a dual portinterface, similar to the topology of a universal serial bus (USB) hub.

This allows interfacing with two separate surgical instrumentssimultaneously. The system 1001 may be able to generate and read handswitch waveforms and be able to handle incoming HP serial buses. Itwould also monitor two separate presence elements in the surgicalinstruments 9007, 9008. In one aspect, the system 1001 may include aunique presence element and may have its own NVM.

Further, according to various aspects, the control circuit 1019 may becontrolled by the generator 1003. The communication between the adapter1015 and connected surgical instruments 9007, 9008 may be relayed togenerator control. The generator 1003 would control the waveformgeneration circuit connected to the adapter 1015 to simultaneouslygenerate HSW signals for surgical instruments 9007, 9008.

The system 1001 may allow surgical instrument activity that can besimultaneously detected/monitored for two surgical instruments, evenduring activation. If upgradeable, the adapter 1015 would be capable ofhandling new surgical instrument communications protocols. Further, fastswitching between surgical instruments may be accomplished.

FIG. 11 illustrates a communication architecture of system 1101 of agenerator 1103, which is one form of the generator 100 (FIGS. 1-3 ), andsurgical instruments 9007, 9008 shown in FIG. 9 . According to FIG. 11 ,the generator 1103 is configured for delivering multiple energymodalities to a plurality of surgical instruments. As discussed hereinthe various energy modalities include, without limitation, ultrasonic,bipolar or monopolar RF, reversible and/or irreversible electroporation,and/or microwave energy modalities. As shown in FIG. 11 , the generator1103 comprises a combined energy modalities power output 1105, a HSWserial interface 1111, a HP serial interface 1113, and a presenceinterface 1109. The generator 1103 provides the combined energymodalities power output 1105 to an adapter 1115. According to the aspectshown in FIG. 11 , communications between the adapter 1115 and thegenerator 1103 may be done solely through serial interfaces, such as theHSW serial and HP serial interfaces 1111, 1113. The generator 1103 mayuse these HSW and HP serial interfaces 1111, 1113 to control whichinstrument the generator 1103 is communicating with. Further, switchingbetween instruments could occur between HSW frames or at a much slowerrate.

The adapter 1115 comprises an energy storage circuit 1117, controlcircuit 1119, an adapter memory 1121 (e.g., a NVM such as an EEPROM), aserial programmable input/output (PIO) integrated circuit 1133, a HSWswitching mechanism 1135, a HP switching mechanism 1137, a presenceswitching mechanism 1139, and a generic adapter 1141. In one aspect, theserial PIO integrated circuit 1133 may be an addressable switch. Theenergy storage circuit 1117 comprises a switching mechanism 1123, energystorage device 1125, storage control component 1127, storage monitoringcomponent 1129, and a device power monitoring component 1131. Thecontrol circuit 1119 may comprise a processor, FPGA, CPLD, PLD,microcontroller, DSP, and/or an ASIC, for example. According to theaspect of FIG. 11 , an FPGA or microcontroller may have limitedfunctionality and may solely comprise functionality for monitoring andcommunicating energy storage.

The switching mechanism 1123 is configured to receive the combinedenergy modalities energy power output 1105 from the generator 1103 andit may be provided to the energy storage device 1125, surgicalinstrument 9007, and/or surgical instrument 9008. The device powermonitoring component 1131 is coupled to the channels for the energystorage device 1125, surgical instrument 9007, surgical instrument 9008,and may monitor where power is flowing.

The control circuit 1119 is coupled to the serial PIO integrated circuit1133 and the serial PIO integrated circuit 1133 is coupled to the HPserial interface 1113 of the generator 1103. The control circuit 1119may receive information regarding charger status flags and switchingcontrols from the serial PIO integrated circuit 1133. Further, thecontrol circuit 1119 is coupled to the HSW switching mechanism 1135, theHP switching mechanism 1137, and the presence switching mechanism 1139.According to the aspect of FIG. 11 , the control circuit 1119 may becoupled to the HSW switching mechanism 1135 and the HP switchingmechanism 1137 for device selection and the control circuit 1119 may becoupled to the presence switching Mechanism 1139 for presence selection.

The HSW switching mechanism 1135, the HP switching mechanism 1137, andthe presence switching mechanism 1139 are coupled to the HSW serialinterface 1111, the HP serial interface 1113, and the presence interface1109 of generator 1103, respectively. Further, the HSW switchingmechanism 1135, the HP switching mechanism 1137, and the presenceswitching mechanism 1139 are coupled to the HSW 1-wire serial protocolinterfaces 9013, 9014, the HP 1-wire serial protocol interfaces 9015,9016, and the presence interfaces 9017, 9018 of the surgical instruments9007, 9008, respectively. Further, the presence switching mechanism 1139is coupled to the generic adapter 1141.

The generator 1103 switches between monitoring the surgical instruments9007, 9008. According to various aspects, this switching may require thegenerator 1103 control to keep track of surgical instruments 9007, 9008and run two separate state machines. The control circuit 1119 will needto remember which surgical instruments are connected, so that it canoutput an appropriate waveform to the ports where appropriate. Thegenerator 1103 may generate/monitor hand switch signals, as well ascommunicating with serial NVM devices, such as the adapter memory 1121.The generator 1103 may maintain constant communication with theactivating surgical instrument for the duration of the activation.

System 1101 also allows for a generic adapter presence element. Whenfirst plugged in or powered on, the adapter 1115 would present thisadapter resistance to the generator 1103. The generator 1103 may thenrelay commands to the adapter 1115 to switch between the differentpresence elements corresponding to the different surgical instruments9007, 9008 connected to it. Accordingly, the generator 1103 is able touse its existing presence resistance circuit. The NVM adapter memory1121 exists on the adapter 1115 for additional identification of theadapter and to provide a level of security. In addition, the adapter1115 has a serial I/O device, i.e., serial PIO integrated circuit 1133.The serial PIO integrated circuit 1133 provides a communication linkbetween the generator 1103 and the adapter 1115.

It may be possible to communicate over the HP serial bus using serialcommunications to HP NVMs and UART style communication to the controlcircuit 1119. According to one aspect, if SLOW serial communication isused (i.e. not overdrive) and a high speed serial protocol is used,system 1101 may need to ensure that the communications protocol does notgenerate a signal that looked like a serial reset pulse. This wouldallow better generator 1103 to adapter 1115 communications and fasterswitching times between surgical instruments 9007, 9008.

The system 1101 uses generator communications protocol and analogcircuit and allows the generator to accomplish decision making. It is asimple and efficient solution that uses a small number of circuitdevices.

FIG. 12 illustrates a communications architecture of system 1201 of agenerator 1203, which is one form of the generator 100 (FIGS. 1-3 ), andsurgical instruments 9007, 9008 shown in FIG. 9 . According to FIG. 12 ,the generator 1203 is configured for delivering multiple energymodalities to a plurality of surgical instruments. As discussed hereinthe various energy modalities include, without limitation, ultrasonic,bipolar or monopolar RF, reversible and/or irreversible electroporation,and/or microwave energy modalities. As shown in FIG. 12 , the generator1203 comprises a combined energy modalities power output 1205, a HSWserial interface 1211, an HP serial interface 1213, and a presenceinterface 1209. In one aspect, the HP serial interface 1213 allows forcommunication with the HP lines of the surgical instruments 9007, 9008and also allows for control of the adapter 1215. The generator 1203provides the combined energy modalities power output 1205 to an adapter1215. The adapter 1215 comprises energy storage circuit 1217, controlcircuit 1219, a serial PIO integrated circuit 1233, HSW #1 circuit 1231,HSW #2 circuit 1271, HP switching mechanism 1221, presence switchingmechanism 1239, switching mechanism 1235, instrument power monitoring1237, and unique presence 1241. As shown in FIG. 12 , the HSW #1 circuit1231 and the HSW #2 circuit 1271 may comprise generation and ADCcircuits. In one aspect, HSW #1 circuit 1231 and/or HSW #2 circuit 1271comprise generation circuit with the ability to generate HSW waveforms.

The control circuit 1219 is coupled to the HSW serial interface 1211 ofthe generator 1203 while the serial PIO integrated circuit 1233 iscoupled to the HP serial interface 1213 as is the HP switching mechanism1221. Further, the control circuit 1119 is coupled to the HSW #1 circuit1231 and the HSW #2 circuit 1271. The control circuit 1119 may comprisea processor, FPGA, CPLD, PLD, microcontroller, and/or ASIC, for example.In the example shown in FIG. 12 , the control circuit 1219 modulates twodevices into at least one digital waveform, which enable the generator1203 to perform the button monitoring and decision making. The controlcircuit 1219 also may allow for communication to two independentsurgical instruments could receive either waveform. The serial PIOintegrated circuit 1233 is further coupled to the HP switching mechanism1221, the instrument power monitoring 1237, and the presence switchingmechanism 1239. The instrument power monitoring 1237 and the serial PIOintegrated circuit 1233 may communicate results and failures to thegenerator 1203.

The switching mechanism 1223 is configured to receive the combinedRF/ultrasonic energy modalities output power 1205 from the generator1203 and it may be provided to the energy storage circuit 1225 or theswitching mechanism 1235. The control circuit 1219 is also coupled tothe storage control 1227 and energy storage monitoring 1229 of theenergy storage circuit 1217. The switching mechanism 1235 may providethe power output received from the switching mechanism 1223 to surgicalinstrument 9007, and/or surgical instrument 9008. The instrument powermonitoring 1237 is coupled to the channels for the power output to thesurgical instrument 9007 and surgical instrument 9008. The instrumentpower monitoring 1237 also may ensure that the switching mechanism 1235is delivering power to correct location.

The HSW #1 circuit 1231 and the HSW #2 circuit 1271 are coupled to theHSW 1-wire serial protocol interfaces 9013, 9014 of the surgicalinstruments 9007, 9008, respectively. The HP switching mechanism 1221 iscoupled to the HP serial interface 1213 of the generator 1203 and to theHP 1-wire serial protocol interfaces 9015, 9016 of the surgicalinstruments 9007, 9008, respectively. Further, the presence switchingmechanism 1239 is coupled to the presence interface 1209 of thegenerator 1203 and to the presence interfaces 9017, 9018 of the surgicalinstruments 9007, 9008, respectively. Further, Presence Switchingmechanism is coupled to the unique presence 1241. In one aspect,different instrument presence elements may be switched on an on-demandbasis using serial I/O or an adapter micro protocol.

A first communications protocol will be used to communicate to thecontrol circuit 1219 on the adapter 1215. The generator 1203 also mayhave the ability to monitor surgical instruments 9007, 9008 at once. Theadapter 1215 may comprise circuit to provide HSW signal generation(e.g., in HSW #1 circuit 1231 and HSW #2 circuit 1271) along with ADCcircuits to interpret this data. The adapter 1215 may modulate twosurgical instrument signals into at least a first waveform and may havethe ability to read in the first and second waveforms. In variousaspects, the second waveforms may be interpreted and translated into theformat of the first waveforms. Further, the first protocol has theability to send 12 bits at 615 bits/sec.

The control circuit 1219 may take the HSW data from surgical instruments9007, 9008 and modulate it into a first protocol. There are a few waysof doing this, but it may mean that surgical instruments 9007, 9008 maycomprise a first protocol functionality. The system 1201 couldcommunicate 4-6 buttons from the surgical instrument 9007 and 4-6buttons from the surgical instrument 9008 in the first protocol frame.Alternatively, the system 1201 could use some form of addressing toaccess the surgical instruments 9007, 9008. The control circuit 1219 mayhave the ability to address separate devices by having the generator1203 send the control circuit 1219 different addresses split into twodifferent address spaces, one for surgical instrument 9007 and one forsurgical instrument 9008.

The HP communications may involve some form of switch that could eitherbe controlled via a serial I/O device or through the control circuit1219 via a first protocol style communication interface from thegenerator 1203. In one aspect, energy storage monitoring 1229 andswitching between surgical instruments 9007, 9008 and charging statescould be handled in this manner as well. Certain first protocoladdresses could be assigned to the data from the energy storage circuit1225 and to the surgical instruments 9007, 9008 themselves. Presenceelements could also be switched in with this format. Further, in oneaspect, the control circuit 1219 may translate frames into a separateformat, which may mean that the control circuit 1219 might need to makesome decisions on whether button presses on surgical instruments 9007,9008 are valid or not. The system 1201 would, however, allow thegenerator 1203 to fully monitor the surgical instruments 9007, 9008 atthe same time time-slicing or handling a new communications protocol onthe HSW serial interface 1211 of the generator 1203. The system 1201uses generator communications to simultaneously detect the activity oftwo surgical instruments, even during activation.

The surgical instruments described herein may be configured to deliverenergy from any of the generators 100, 200, 300, 400, 500, 9001, 1003,1103, 1203 discussed herein. The energy may be dynamically changed basedon the type of tissue being treated by an end effector of a surgicalinstrument and various characteristics of the tissue. For concisenessand clarity of disclosure any of the generators 100, 200, 300, 400, 500,9001, 1003, 1103, 1203 described hereinabove will be describedhereinbelow as generator 100. It will be appreciated that in thiscontext the generator 100 may comprise functional circuits andalgorithms described in connection with the generators 200, 300, 400,500, 9001, 1003, 1103, 1203, taken alone or in combination, as may beappropriate without departing from the scope of the present disclosure.Accordingly, the reader is directed to the description of the functionalblocks of the generators 200, 300, 400, 500, 9001, 1003, 1103, 1203, inFIGS. 1-3 and 5-12 for additional details that may be necessary tounderstand and practice the logic flow diagrams described hereinbelow inconnection with the generator 100.

In one aspect, the generator 100 is coupled to the combination RFelectrosurgical/ultrasonic instrument 108 shown and described inconnection with FIG. 2 . The generator 100 may include an algorithm forcontrolling the power output of the generator 100 delivered to the endeffector 125 of the surgical instrument 108. The power output may bevaried based on feedback that represents the tissue type located clamparm 146 and the ultrasonic blade 149 of the end effector 125.Accordingly, the energy profile of the generator 100 may be dynamicallyaltered during the procedure based on the type of tissue being effectedby the end effector 125 of the surgical instrument 108. Variousalgorithms for determining tissue type are described in U.S. patentapplication Ser. No. 15/177,430, titled SURGICAL INSTRUMENT WITH USERADAPTABLE TECHNIQUES, filed on Jun. 9, 2016, the contents of which areincorporated herein by reference in their entirety. The generator 100 isconfigurable for use with different surgical instruments of differenttypes including, for example, the multifunction surgical instrument 108that integrates electrosurgical RF and ultrasonic energies deliveredsimultaneously from the generator 100.

According to the present disclosure, the generator 100 may be configuredto output an analog output signal usually in the form of a sinusoid atsome predetermined frequency or wavelength. The output signal may becharacterized by a variety of different types, frequencies, and shapesof electrical signal waveforms suitable for effecting a desired therapyto the tissue. Electrical signal waveforms are basically visualrepresentations of the variation of voltage or current along thevertical axis over time along the horizontal axis represent the shape ofthe waveform as shown in FIGS. 13-17 , for example. The generator 100includes circuitry and algorithms configured to generate many differenttypes of electrical signal waveforms. In one aspect, the generator 100is configured to generate electrical signal waveforms using digitalsignal processing techniques. In one aspect, the generator 100 comprisesa memory, DDS circuit (FIGS. 13, 14 ), a DAC circuit, and a poweramplifier configured as discussed hereinbelow to generate a variety ofcontinuous output signals in a variety of electrical waveforms selectedbased on the tissue type or other feedback information.

In one aspect, the generator 100 is configured to generate theelectrical signal waveform digitally such that the desired using apredetermined number of phase points stored in a lookup table todigitize the wave shape. The phase points may be stored in a tabledefined in a memory, a FPGA, or any suitable non-volatile memory. FIG.13 depicts one aspect of a fundamental architecture for a digitalsynthesis circuit such as a direct digital synthesis (DDS) circuit 1300configured to generate a plurality of wave shapes for the electricalsignal waveform. The generator 100 software and digital controls maycommand the FPGA to scan the addresses in the lookup table 1304 which inturn provides varying digital input values to a DAC circuit 1308 thatfeeds a power amplifier. The addresses may be scanned according to afrequency of interest. Using such a lookup table 1304 enables generatingvarious types of wave shapes that can be fed into tissue or into atransducer, an RF electrode, multiple transducers simultaneously,multiple RF electrodes simultaneously, or a combination of RF andultrasonic instruments. Furthermore, multiple wave shape lookup tables1304 can be created, stored, and applied to tissue from a singlegenerator 100.

The waveform signal may be configured to control at least one of anoutput current, an output voltage, or an output power of an ultrasonictransducer and/or an RF electrode, or multiples thereof (e.g. two ormore ultrasonic transducers and/or two or more RF electrodes). Further,where the surgical instrument comprises an ultrasonic components, thewaveform signal may be configured to drive at least two vibration modesof an ultrasonic transducer of the at least one surgical instrument.Accordingly, a generator may be configured to provide a waveform signalto at least one surgical instrument wherein the waveform signalcorresponds to at least one wave shape of a plurality of wave shapes ina table. Further, the waveform signal provided to the two surgicalinstruments may comprise two or more wave shapes. The table may compriseinformation associated with a plurality of wave shapes and the table maybe stored within the generator. In one embodiment or example, the tablemay be a direct digital synthesis table, which may be stored in an FPGAof the generator. The table may be addressed by anyway that isconvenient for categorizing wave shapes. According to one embodiment,the table, which may be a direct digital synthesis table, is addressedaccording to a frequency of the waveform signal. Additionally, theinformation associated with the plurality of wave shapes may be storedas digital information in the table.

The analog electrical signal waveform may be configured to control atleast one of an output current, an output voltage, or an output power ofan ultrasonic transducer and/or an RF electrode, or multiples thereof(e.g., two or more ultrasonic transducers and/or two or more RFelectrodes). Further, where the surgical instrument comprises ultrasoniccomponents, the analog electrical signal waveform may be configured todrive at least two vibration modes of an ultrasonic transducer of the atleast one surgical instrument. Accordingly, the generator 100 may beconfigured to provide an analog electrical signal waveform to at leastone surgical instrument wherein the analog electrical signal waveformcorresponds to at least one wave shape of a plurality of wave shapesstored in a lookup table 1304. Further, the analog electrical signalwaveform provided to the two surgical instruments may comprise two ormore wave shapes. The lookup table 1304 may comprise informationassociated with a plurality of wave shapes and the lookup table 1304 maybe stored either within the generator 100 or the surgical instrument. Inone embodiment or example, the lookup table 1304 may be a direct digitalsynthesis table, which may be stored in an FPGA of the generator 100 orthe surgical instrument. The lookup table 1304 may be addressed byanyway that is convenient for categorizing wave shapes. According to oneaspect, the lookup table 1304, which may be a direct digital synthesistable, is addressed according to a frequency of the desired analogelectrical signal waveform. Additionally, the information associatedwith the plurality of wave shapes may be stored as digital informationin the lookup table 1304.

With the widespread use of digital techniques in instrumentation andcommunications systems, a digitally-controlled method of generatingmultiple frequencies from a reference frequency source has evolved andis referred to as direct digital synthesis. The basic architecture isshown in FIG. 13 . In this simplified block diagram, a DDS circuit iscoupled to a processor, controller, or a logic device of the generator100 and to a memory circuit located either in the generator 100 or thesurgical instrument 104, 106, 108 (FIG. 1 ). The DDS circuit 1300comprises an address counter 1302, lookup table 1304, a register 1306, aDAC circuit 1308, and a filter 1312. A stable clock f_(c) is received bythe address counter 1302 and the register 1306 drives aprogrammable-read-only-memory (PROM) which stores one or more integralnumber of cycles of a sinewave (or other arbitrary waveform) in a lookuptable 1304. As the address counter 1302 steps through each memorylocation, values stored in the lookup table 1304 are written to aregister 1306, which is coupled to a DAC circuit 1308. The correspondingdigital amplitude of the signal at each location of the lookup table1304 drives the DAC circuit 1308, which in turn generates an analogoutput signal 1310. The spectral purity of the analog output signal 1310is determined primarily by the DAC circuit 1308. The phase noise isbasically that of the reference clock f_(c). The first analog signal1310 output from the DAC circuit 1308 is filtered by the filter 1312 anda second analog output signal 1314 output by the filter 1312 is providedto an amplifier having an output coupled to the output of the generator100. The second analog output signal has a frequency f_(out).

Because the DDS circuit 1300 is a sampled data system, issues involvedin sampling must be considered: quantization noise, aliasing, filtering,etc. For instance, the higher order harmonics of the DAC circuit 1308output frequencies fold back into the Nyquist bandwidth, making themunfilterable, whereas, the higher order harmonics of the output ofphase-locked-loop (PLL) based synthesizers can be filtered. The lookuptable 1304 contains signal data for an integral number of cycles. Thefinal output frequency f_(out) can be changed changing the referenceclock frequency f_(c) or by reprogramming the PROM.

The DDS circuit 1300 may comprise multiple lookup tables 1304 where eachlookup table 1304 stores a waveform represented by a predeterminednumber of samples, wherein the samples define a predetermined shape ofthe waveform. Thus multiple waveforms, each having a unique shape, canbe stored in multiple lookup tables 1304 to provide different tissuetreatments based on instrument settings or tissue feedback. Examples ofwaveforms include high crest factor RF electrical signal waveforms forsurface tissue coagulation, low crest factor RF electrical signalwaveform for deeper tissue penetration, and electrical signal waveformsthat promote efficient touch-up coagulation. In one aspect, the DDScircuit 1300 can create multiple wave shape lookup tables 1304 andduring a tissue treatment procedure (e.g., “on-the-fly” or in virtualreal time based on user or sensor inputs) switch between different waveshapes stored in different lookup tables 1304 based on the tissue effectdesired and/or tissue feedback. Accordingly, switching between waveshapes can be based on tissue impedance and other factors, for example.In other aspects, the lookup tables 1304 can store electrical signalwaveforms shaped to maximize the power delivered into the tissue percycle (i.e., trapezoidal or square wave). In other aspects, the lookuptables 1304 can store wave shapes synchronized in such way that theymake maximizing power delivery by the multifunction surgical instrument108 when it delivering both RF and ultrasonic drive signals. In yetother aspects, the lookup tables 1304 can store electrical signalwaveforms to drive both ultrasonic and RF therapeutic, and/orsub-therapeutic, energy simultaneously while maintaining ultrasonicfrequency lock. Custom wave shapes specific to different instruments andtheir tissue effects can be stored in the non-volatile memory of thegenerator 100 or in the non-volatile memory (e.g., EEPROM) of themultifunction surgical instrument 108 and be fetched upon connecting themultifunction surgical instrument 108 to the generator 100. An exampleof an exponentially damped sinusoid, as used in many high crest factor“coagulation” waveforms is shown in FIG. 15 .

A more flexible and efficient implementation of the DDS circuit 1300employs a digital circuit called a Numerically Controlled Oscillator(NCO). A block diagram of a more flexible and efficient digitalsynthesis circuit such as a DDS circuit 1400 is shown in FIG. 15 . Inthis simplified block diagram, a DDS circuit 1400 is coupled to aprocessor, controller, or a logic device of the generator 100 and to amemory circuit located either in the generator 100 or the surgicalinstrument 104, 106, 108 (FIG. 1 ). The DDS circuit 1400 comprises aload register 1402, a parallel delta phase register 1404, an addercircuit 1416, a phase register 1408, a lookup table 1410(phase-to-amplitude converter), a DAC circuit 1412, and a filter 14142.The adder circuit 1416 and the phase register 1408 a form part of aphase accumulator 1406. A clock signal f_(c) is applied to the phaseregister 1408 and the DAC circuit 1412. The load register 1402 receivesa tuning word that specifies output frequency as a fraction of thereference clock frequency f_(c). The output of the load register 1402 isprovided to a parallel delta phase register 1404 with a tuning word M.

The DDS circuit 1400 includes a sample clock that generates a clockfrequency f_(c), a phase accumulator 1406, and a lookup table 1410(e.g., phase to amplitude converter). The content of the phaseaccumulator 1406 is updated once each clock cycle f_(c). Each time thephase accumulator 1406 is updated, the digital number, M, stored in theparallel delta phase register 1404 is added to the number in the phaseregister 1408 by an adder circuit 1416. Assuming that the number in theparallel delta phase register 1404 is 00 . . . 01 and that the initialcontents of the phase accumulator 1406 is 00 . . . 00. The phaseaccumulator 1406 is updated by 00 . . . 01 on each clock cycle. If thephase accumulator 1406 is 32-bits wide, 232 clock cycles (over 4billion) are required before the phase accumulator 1406 returns to 00 .. . 00, and the cycle repeats.

The truncated output 1418 of the phase accumulator 1406 is provided to aphase-to amplitude converter lookup table 1410 and the output of thelookup table 1410 is coupled to a DAC circuit 1412. The truncated output1418 of the phase accumulator 1406 serves as the address to a sine (orcosine) lookup table. Each address in the lookup table corresponds to aphase point on the sinewave from 0° to 360°. The lookup table 1410contains the corresponding digital amplitude information for onecomplete cycle of a sinewave. The lookup table 1410 therefore maps thephase information from the phase accumulator 1406 into a digitalamplitude word, which in turn drives the DAC circuit 1412. The output ofthe DAC circuit is a first analog signal 1420 and is filtered by afilter 1414. The output of the filter 1414 is a second analog signal1422, which is provided to a power amplifier 212, 326, 426, 506 (FIGS.5-8 ) coupled to the output of the generator 100.

In one aspect, the electrical signal waveform may be digitized into 1024(2¹⁰) phase points, although the wave shape may be digitized is anysuitable number of 2^(n) phase points ranging from 256 (2⁸) to281,474,976,710,656 (2⁴⁸), where n is a positive integer, as shown inTABLE 1. The electrical signal waveform may be expressed asA_(n)(θ_(n)), where a normalized amplitude A_(n) at a point n isrepresented by a phase angle θ_(n) is referred to as a phase point atpoint n. The number of discrete phase points n determines the tuningresolution of the DDS circuit 1400 (as well as the DDS circuit 1300shown in FIG. 13 ).

TABLE 1 n Number of Phase Points 2^(n) 8 256 10 1,024 12 4,096 14 16,38416 65,536 18 262,144 20 1,048,576 22 4,194,304 24 16,777,216 2667,108,864 28 268,435,456 . . . . . . 32 4,294,967,296 . . . . . . 48281,474,976,710,656 . . . . . .

The generator 100 algorithms and digital control circuits scan theaddresses in the lookup table 1410, which in turn provides varyingdigital input values to the DAC circuit 1412 that feeds the filter 1414and the power amplifier. The addresses may be scanned according to afrequency of interest. Using the lookup table enables generating varioustypes of shapes that can be converted into an analog output signal bythe DAC circuit 1412, filtered by the filter 1414, amplified by thepower amplifier coupled to the output of the generator 100, and fed tothe tissue in the form of RF energy or fed to an ultrasonic transducerand applied to the tissue in the form of ultrasonic vibrations whichdeliver energy to the tissue in the form of heat. The output of theamplifier can be applied to a single RF electrode, multiple RFelectrodes simultaneously, a single ultrasonic transducer, multipleultrasonic transducers simultaneously, or a combination of RF andultrasonic transducers, for example. Furthermore, multiple wave shapetables can be created, stored, and applied to tissue from a singlegenerator 100.

With reference back to FIG. 14 , for n=32, and M=1, the phaseaccumulator 1406 steps through each of 2³² possible outputs before itoverflows and restarts. The corresponding output wave frequency is equalto the input clock frequency divided by 2³². If M=2, then the phaseregister 1408 “rolls over” twice as fast, and the output frequency isdoubled. This can be generalized as follows.

For an n-bit phase accumulator 1406 (n generally ranges from 24 to 32 inmost DDS systems, but as previously discussed n may be selected from awide range of options), there are 2^(n) possible phase points. Thedigital word in the delta phase register, M, represents the amount thephase accumulator is incremented each clock cycle. If fc is the clockfrequency, then the frequency of the output sinewave is equal to:

$\begin{matrix}{f_{o} = \frac{M \cdot f_{c}}{2^{n}}} & {{Eq}.1}\end{matrix}$

Equation 1 is known as the DDS “tuning equation.” Note that thefrequency resolution of the system is equal to f_(c)/2^(n). For n=32,the resolution is greater than one part in four billion. In one aspectof the DDS circuit 1400, not all of the bits out of the phaseaccumulator 1406 are passed on to the lookup table 1410, but aretruncated, leaving only the first 13 to 15 most significant bits (MSBs),for example. This reduces the size of the lookup table 1410 and does notaffect the frequency resolution. The phase truncation only adds a smallbut acceptable amount of phase noise to the final output.

The electrical signal waveform may be characterized by a current,voltage, or power at a predetermined frequency. Further, where themultifunction surgical instrument 108 comprises ultrasonic components,the electrical signal waveform may be configured to drive at least twovibration modes of an ultrasonic transducer of the at least onemultifunction surgical instrument 108. Accordingly, the generator 100may be configured to provide an electrical signal waveform to at leastone multifunction surgical instrument 108 wherein the electrical signalwaveform is characterized by a predetermined wave shape stored in thelookup table 1410 (or lookup table 1304 FIG. 13 ). Further, theelectrical signal waveform may be a combination of two or more waveshapes. The lookup table 1410 may comprise information associated with aplurality of wave shapes. In one aspect or example, the lookup table1410 may be generated by the DDS circuit 1400 and may be referred to asa direct digital synthesis table. DDS works by first storing a largerepetitive waveform in onboard memory. Any single cycle of a waveform(sine, triangle, square, arbitrary) can be represented by apredetermined number of phase points as shown in TABLE 1 and stored intomemory. Once the waveform is stored into memory, it can be generated atvery precise frequencies. The direct digital synthesis table may bestored in a non-volatile memory of the generator 100 and/or may beimplemented with a FPGA circuit in the generator 100. The lookup table1410 may be addressed by any suitable technique that is convenient forcategorizing wave shapes. According to one aspect, the lookup table 1410is addressed according to a frequency of the electrical signal waveform.Additionally, the information associated with the plurality of waveshapes may be stored as digital information in a memory or as part ofthe lookup table 1410.

In one aspect, the generator 100 may be configured to provide electricalsignal waveforms to at least two surgical instruments simultaneously.The generator 100 also may be configured to provide the electricalsignal waveform, which may be characterized two or more wave shapes, viaa single output channel of the generator 100 to the two surgicalinstruments simultaneously. For example, in one aspect the electricalsignal waveform comprises a first electrical signal to drive anultrasonic transducer (e.g., ultrasonic drive signal), a second RF drivesignal, and/or a combination of both. In addition, an electrical signalwaveform may comprise a plurality of ultrasonic drive signals, aplurality of RF drive signals, and/or a combination of a plurality ofultrasonic and RF drive signals.

In addition, a method of operating the generator 100 according to thepresent disclosure comprises generating an electrical signal waveformand providing the generated electrical signal waveform to at least onemultifunction surgical instrument 108, where generating the electricalsignal waveform comprises receiving information associated with theelectrical signal waveform from a memory. The generated electricalsignal waveform comprises at least one wave shape. Furthermore,providing the generated electrical signal waveform to the at least onemultifunction surgical instrument 108 comprises providing the electricalsignal waveform to at least two surgical instruments simultaneously.

The generator 100 as described herein may allow for the generation ofvarious types of direct digital synthesis tables. Examples of waveshapes for RF/Electrosurgery signals suitable for treating a variety oftissue generated by the generator 100 include RF signals with a highcrest factor (which may be used for surface coagulation in RF mode), alow crest factor RF signals (which may be used for deeper tissuepenetration), and waveforms that promote efficient touch-up coagulation.The generator 100 also may generate multiple wave shapes employing adirect digital synthesis lookup table 1410 and, on the fly, can switchbetween particular wave shapes based on the desired tissue effect.Switching may be based on tissue impedance and/or other factors.

In addition to traditional sine/cosine wave shapes, the generator 100may be configured to generate wave shape(s) that maximize the power intotissue per cycle (i.e., trapezoidal or square wave). The generator 100may provide wave shape(s) that are synchronized to maximize the powerdelivered to the load when driving both RF and ultrasonic signalssimultaneously and to maintain ultrasonic frequency lock, provided thatthe generator 100 includes a circuit topology that enablessimultaneously driving RF and ultrasonic signals. Further, custom waveshapes specific to instruments and their tissue effects can be stored ina non-volatile memory (NVM) or an instrument EEPROM and can be fetchedupon connecting the multifunction surgical instrument 108 to thegenerator 100.

The DDS circuit 1400 may comprise multiple lookup tables 1304 where eachlookup table 1410 stores a waveform represented by a predeterminednumber of phase points (also may be referred to as samples), wherein thephase points define a predetermined shape of the waveform. Thus multiplewaveforms, each having a unique shape, can be stored in multiple lookuptables 1410 to provide different tissue treatments based on instrumentsettings or tissue feedback. Examples of waveforms include high crestfactor RF electrical signal waveforms for surface tissue coagulation,low crest factor RF electrical signal waveform for deeper tissuepenetration, and electrical signal waveforms that promote efficienttouch-up coagulation. In one aspect, the DDS circuit 1400 can createmultiple wave shape lookup tables 1410 and during a tissue treatmentprocedure (e.g., “on-the-fly” or in virtual real time based on user orsensor inputs) switch between different wave shapes stored in differentlookup tables 1410 based on the tissue effect desired and/or tissuefeedback. Accordingly, switching between wave shapes can be based ontissue impedance and other factors, for example. In other aspects, thelookup tables 1410 can store electrical signal waveforms shaped tomaximize the power delivered into the tissue per cycle (i.e.,trapezoidal or square wave). In other aspects, the lookup tables 1410can store wave shapes synchronized in such way that they make maximizingpower delivery by the multifunction surgical instrument 108 when itdelivering both RF and ultrasonic drive signals. In yet other aspects,the lookup tables 1410 can store electrical signal waveforms to driveboth ultrasonic and RF therapeutic, and/or sub-therapeutic, energysimultaneously while maintaining ultrasonic frequency lock. Custom waveshapes specific to different instruments and their tissue effects can bestored in the non-volatile memory of the generator 100 or in thenon-volatile memory (e.g., EEPROM) of the multifunction surgicalinstrument 108 and be fetched upon connecting the multifunction surgicalinstrument 108 to the generator 100. An example of an exponentiallydamped sinusoid, as used in many high crest factor “coagulation”waveforms is shown in FIG. 19 .

Examples of waveforms representing energy for delivery from a generatorare illustrated in FIGS. 15-19 . FIG. 15 illustrates an example graph600 showing first and second individual waveforms representing an RFoutput signal 602 and an ultrasonic output signal 604 superimposed onthe same time and voltage scale for comparison purposes. These outputsignals 602, 604 are provided at the ENERGY output of the generator 100.Time (t) is shown along the horizontal axis and voltage (V) is shownalong the vertical axis. The RF output signal 602 has a frequency ofabout 330 kHz RF and a peak-to-peak voltage of ±1V. The ultrasonicoutput signal 604 has a frequency of about 55 kHz and a peak-to-peakvoltage of ±1V. It will be appreciated that the time (t) scale along thehorizontal axis and the voltage (V) scale along the vertical axis arenormalized for comparison purposes and may be different actualimplementations, or represent other electrical parameters such ascurrent.

FIG. 16 illustrates an example graph 610 showing the sum of the twooutput signals 602, 604 shown in FIG. 15 . Time (t) is shown along thehorizontal axis and voltage (V) is shown along the vertical axis. Thesum of the RF output signal 602 and the ultrasonic output signal 604shown in FIG. 15 produces a combined output signal 612 having a 2Vpeak-to-peak voltage, which is twice the amplitude of the original RFand ultrasonic signals shown (1V peak-to-peak) shown in FIG. 15 . Anamplitude of twice the original amplitude can cause problems with theoutput section of the generator, such as distortion, saturation,clipping of the output, or stresses on the output components. Thus, themanagement of a single combined output signal 612 that has multipletreatment components is an important aspect of the generator 500 shownin FIG. 8 . There are a variety of ways to achieve this management. Inone form, one of the two RF or ultrasonic output signals 602, 604 can bedependent on the peaks of the other output signal. In one aspect, the RFoutput signal 602 may depend on the peaks of the ultrasonic signal 604,such that the output is reduced when a peak is anticipated. Such afunction and resulting waveform is shown in FIG. 17

For example, FIG. 17 illustrates an example graph 620 showing a combinedoutput signal 622 representative of a dependent sum of the outputsignals 602, 604 shown in FIG. 15 . Time (t) is shown along thehorizontal axis and voltage (V) is shown along the vertical axis. Asshown in FIG. 17 , the RF output signal 602 component of FIG. 15 dependson the peaks of the ultrasonic output signal 604 component of FIG. 15such that the amplitude of the RF output signal component of thedependent sum combined output signal 622 is reduced when an ultrasonicpeak is anticipated. As shown in the example graph 620 in FIG. 17 , thepeaks have been reduced from 2 to 1.5. In another form, one of theoutput signals is a function of the other output signal.

For example, FIG. 18 illustrates an example graph of an analog waveform630 showing an output signal 632 representative of a dependent sum ofthe output signals 602, 604 shown in FIG. 15 . Time (t) is shown alongthe horizontal axis and voltage (V) is shown along the vertical axis. Asshown in FIG. 18 , the RF output signal 602 is a function of theultrasonic output signal 604. This provides a hard limit on theamplitude of the output. As shown in FIG. 18 , the ultrasonic outputsignal 604 is extractable as a sine wave while the RF output signal 602has distortion but not in a way to affect the coagulation performance ofthe RF output signal 602.

A variety of other techniques can be used for compressing and/orlimiting the waveforms of the output signals. It should be noted thatthe integrity of the ultrasonic output signal 604 (FIG. 15 ) can be moreimportant than the integrity of the RF output signal 602 (FIG. 15 ) aslong as the RF output signal 602 has low frequency components for safepatient levels so as to avoid neuro-muscular stimulation. In anotherform, the frequency of an RF waveform can be changed on a continuousbasis in order to manage the peaks of the waveform. Waveform control isimportant as more complex RF waveforms, such as a coagulation-typewaveform 642, as illustrated in the graph 640 shown in FIG. 19 , areimplemented with the system. Again, time (t) is shown along thehorizontal axis and voltage (V) is shown along the vertical axis. Thecoagulation-type waveform 642 illustrated in FIG. 19 has a crest factorof 5.8, for example.

FIG. 20 illustrates one cycle of a digital electrical signal waveform1800 of the analog waveform 630 shown in FIG. 18 . The horizontal axisrepresents Time (t) and the vertical axis represents digital phasepoints. The digital electrical signal waveform 1800 is a digital versionof the desired analog waveform 630 shown in FIG. 18 , for example. Thedigital electrical signal waveform 1800 is generated by storing anamplitude phase point 1802 that represents the amplitude at each clockcycle T_(clk) over one cycle or period T_(o). The digital electricalsignal waveform 1800 is generated over one period T_(o) by any suitabledigital processing circuit. The amplitude phase points are digital wordsstored in a memory circuit. In the example illustrated in FIG. 20 , thedigital word is a six-bit word that is capable of storing the amplitudephase points with a resolution of 2⁶ or 64 bits. It will be appreciatedthat the example shown in FIG. 20 is for illustrative purposes and inactual implementations the resolution can be much higher. The digitalamplitude phase points 1802 over one cycle T_(o) are stored in thememory as a string of string words in a lookup table 11304, 1410 asdescribed in connection with FIGS. 13 and 14 , for example. To generatethe analog version of the waveform 630, the amplitude phase points 1802are read sequentially from the memory from 0 to T_(o) at each clockcycle T_(clk) and are converted by a DAC circuit 1308, 1412, alsodescribed in connection with FIGS. 13 and 14 . Additional cycles can begenerated by repeatedly reading the amplitude phase points 1802 of thedigital electrical signal waveform 1800 the from 0 to T_(o) for as manycycles or periods as may be desired. The smooth analog version of thewaveform 630 (also shown in FIG. 18 ) is achieved by filtering theoutput of the DAC circuit 1308, 1412 by a filter 1312, 1414 (FIGS. 13and 14 ). The filtered analog output signal 1314, 1422 (FIGS. 13 and 14) is applied to the input of a power amplifier 212, 326, 426, 506 (FIGS.5-8 ).

FIGS. 21-23 are logic flow diagrams of methods 1500, 1600, 1700 ofgenerating an electrical signal waveform by any of the generators 100,200, 300, 400, 500, 9001, 1003, 1103, 1203 described herein. Forconciseness and clarity the generators 100, 200, 300, 400, 500, 9001,1003, 1103, 1203 will be referred to as the generator 100. Accordingly,the generator 100 is representative of the generators 200, 300, 400,500, 9001, 1003, 1103, 1203 described herein. The methods 1500, 1600,1700 will be described with reference to FIGS. 1, 13, 14 , and and FIGS.5-8 . The generator 100 comprises a digital processing circuit, a DDScircuit 1300, 1400, a memory circuit defining a lookup table 1304, 1410,and DAC circuit 1308, 1412, as described herein. The digital processingcircuit may comprise any digital processing circuit, microprocessor,microcontroller, digital signal processor, logic device comprisingcombinational logic or sequential logic circuits, or any suitabledigital circuit. The memory circuit may be located either in thesurgical instrument 104, 106, 108 or the generator 100. In one aspect,the DDS circuit 1300, 1400 is coupled to the digital processing circuitand the memory circuit. In another aspect, the memory circuit is part ofthe DDS circuit 1300, 1400.

In various aspects, the generator 100 may be configured to drivemultiple surgical instruments 104, 106, 108 simultaneously. Thus thegenerator 100 may be configured to drive the surgical instruments 104,106, 108 in multiple vibration modes to achieve a longer active lengthat the ultrasonic blade 128, 149 and to create different tissue effects.

According to one of the present disclosure, the generator 100 may beconfigured to provide ultrasonic electrical signal waveforms defining anumber of wave shapes to the surgical instrument 104, 108 to provide adesired therapy to tissue at the end effector 122, 125.

In one aspect, the generator 100 may be configured to generate a digitalelectrical signal waveform such that the desired wave shape can bedigitized by a number of phase points or samples which are stored in alookup table 1304, 1410 defined in volatile or non-volatile memory asdiscussed above in connection with FIGS. 13 and 14 , for example. Thephase points or samples may be stored in the lookup table 1304, 1410defined in a FPGA, for example. The wave shape may be digitized into anumber of phase points or samples as shown in TABLE 1. In one aspect,the wave shape may be digitized into 1024 phase points, for example. Thedigital processing circuit of the generator 100 may control by softwareor digital control the FPGA to scan the addresses in the lookup table1304, 1410 which in turn provides varying digital input values to theDAC circuit 1308, 1412 that feeds a power amplifier 212, 326, 426, 506.The addresses may be scanned according to a frequency of interest. Usingsuch the lookup table 1304, 1410 enables generating various types ofwave shapes that can be used to drive the surgical instruments 104, 106,108 simultaneously. Furthermore, multiple wave shape lookup tables 1304,1410 can be created, stored, and applied to tissue from a singlegenerator 100.

In one aspect, the electrical signal waveforms may be defined by anoutput current, an output voltage, an output power, or frequencysuitable to drive the ultrasonic transducer 120 or multiple ultrasonictransducers (e.g. two or more ultrasonic transducers). In the case ofthe multifunction surgical instrument 108, in addition to driving theultrasonic transducer 120, the electrical signal waveforms may bedefined by an output current, an output voltage, an output power, orfrequency suitable to drive the electrodes located in the end effector125 of the multifunction surgical instrument 108.

Further, in one aspect where the surgical instrument 104, 108 comprisesultrasonic components, the electrical signal waveform may be configuredto drive at least two vibration modes of the ultrasonic transducer 120.Accordingly, a generator 100 may be configured to provide a electricalsignal waveform to at least one surgical instrument 104, 108 wherein theelectrical signal waveform defines at least one wave shape selected outof a plurality of wave shapes stored in the lookup table 1304, 1410.Further, the electrical signal waveform provided to the two surgicalinstruments 104, 108 may define two or more wave shapes. The lookuptable 1304, 1410 may comprise information associated with a plurality ofwave shapes and the lookup table 1304, 1410 may be stored in a memorylocated either in the generator 100 or the surgical instruments 104,108. In one embodiment or example, the lookup table 1304, 1410 may be adirect digital synthesis table, which may be stored in an FPGA locatedin the generator 100 or the surgical instruments 104, 108. The lookuptable 1304, 1410 may be addressed using any suitable technique forcategorizing wave shapes. According to one aspect, the DDS lookup table1304, 1410 may be addressed according to the frequency of the electricalsignal waveform. Additional information associated with the plurality ofwave shapes also may be stored as digital information in the DDS lookuptable 1304, 1410.

In one aspect, the generator 100 may comprise a DAC circuit 1308, 1412and a power amplifier 212, 326, 426, 506. The DAC circuit 1308, 1412 iscoupled to the power amplifier 212, 326, 426, 506 such that the DACcircuit 1308, 1412 provides the analog electrical signal waveform to afilter 1312, 1414 and the output of the filter 1312, 1414 is provided tothe power amplifier 212, 326, 426, 506. The output of the poweramplifier 212, 326, 426, 506 is provided to the surgical instrument 104,108.

Further, in one aspect the generator 100 may be configured to providethe electrical signal waveform to the surgical instruments 104, 106, 108simultaneously. This may be accomplished through a single output port orchannel of the generator 100. The generator 100 also may be configuredto provide the electrical signal waveform, which may define two or morewave shapes, via a single output port or channel to the two surgicalinstruments 104, 108 simultaneously. The analog signal output of thegenerator 100 may define multiple wave shapes to one or more than onesurgical instruments 104, 108. For example, in one aspect, theelectrical signal waveform comprises multiple ultrasonic drive signals.In another aspect, the electrical signal waveform comprises multipleultrasonic drive signals and one or more than one RF signals.Accordingly, an electrical signal waveform output of the generator 100may comprise multiple ultrasonic drive signals, multiple RF signals,and/or a combination of multiple ultrasonic drive signals and a RFsignals.

In one aspect, the generator 100 as described herein may allow for thecreation of various types of DDS lookup tables 1304, 1410 within an FPGAlocated in the generator 100. Some examples of the wave shapes that maybe produced by the generator 100 include high crest factor signals(which may be used for surface coagulation), low crest factor signals(which may be used for deeper tissue penetration), and electrical signalwaveforms that promote efficient touch-up coagulation. The generator 100also may create multiple wave shape lookup tables 1304, 1410. Thegenerator 100 can be configured to switch between different electricalsignal waveforms for diving ultrasonic transducers 120 during aprocedure (e.g., “on-the-fly” or in virtual real time based on user orsensor inputs) based on desired tissue effects or feedback signalsassociated with the state of the tissue located in the end effector 122,125. Switching may be based on tissue impedance, tissue temperature,state of coagulation, state of dissection, and/or other factors.

In one aspect, the generator 100 as described herein also may provide,in addition to the traditional sine wave shape, wave shapes thatmaximizes the power into tissue per cycle (i.e. trapezoidal, square, ortriangular wave shapes). It also may provide wave shapes that aresynchronized in a manner that would maximize power delivery in the caseof an electrical signal waveform comprises RF and ultrasonic signalcomponents to drive ultrasonic and RF therapeutic energy simultaneouslywhile maintaining ultrasonic frequency lock. Further, custom wave shapesspecific to various types of surgical instruments 104, 108 and theirtissue effects can be stored in a lookup table 1304, 1410 memory locatedin the generator 100 or the surgical instrument 104, 108, where thememory may be a volatile (RAM) or non-volatile (EEPROM) memory. The waveshape may be fetched from the lookup table 1304, 1410 memory uponconnecting the surgical instrument 104, 108 to the generator 100.

With reference to FIG. 21 , in accordance with the method 1500, thegenerator 100 is configured to generate 1502 one or more than oneelectrical signal waveform and provide 1504 the generated one or morethan one electrical signal waveform to a surgical instrument 104, 106,108. The generator 100 generates 1502 one or more than one digitalelectrical signal waveform from one or more lookup tables 1304, 1410 asdescribed in connection with FIGS. 13 and 14 . The one or more than onedigital electrical signal waveform may be defined by a plurality of waveshapes that are combined to form a complex waveform. The lookup tables1304, 1410 may be defined in a memory circuit in communication with adigital processing circuit of the generator 100 or the surgicalinstrument 104, 106, 108. In one aspect, the lookup tables 1304, 1410may be DDS lookup tables that can be addressed according to a desiredfrequency of the electrical signal waveforms. In one aspect, the digitalelectrical signal waveform is a combination of at least two wave shapes.The combined digital electrical signal waveform is provided to the DACcircuit 1308, 1412 circuit and may be filtered by the filter 1312, 1414and amplified by a power amplifier 212, 326, 426, 506. The combinedanalog electrical signal waveform may be an ultrasonic drive signalhaving a frequency of 55 kHz or an RF signal having a frequency of 330kHz or a combination of the ultrasonic drive signal and the RF signal.

In one aspect, the method 1500 the power amplifier 212, 326, 426, 506amplifies the analog signal 1310, 1420 output of the DAC circuit 1308,1412. In addition, according to the method 1500, the digital processingcircuit stores phase points of a digital electrical signal waveform inthe lookup table 1304, 1410 defined by the memory circuit. The digitalprocessing circuit stores phase points of multiple digital electricalsignal waveforms in corresponding multiple lookup tables 1304, 1410defined by the memory circuit or other memory circuits. Each of thedigital electrical signal waveforms is represented by a predeterminednumber of phase points. Each of the predetermined number of phase pointsdefines a different wave shape. In accordance with the method 1500, thedigital processing circuit receives a feedback signal associated withtissue parameters and modifies the predetermined wave shape according tothe feedback signal.

In one aspect, the digital electrical signal waveform represents a RFsignal waveform, an ultrasonic signal waveform, or a combinationthereof. In one aspect, the digital electrical signal waveformrepresents a combination of two waveforms having different amplitudes.In one aspect, the digital electrical signal waveform represents acombination of two waveforms having different frequencies. In oneaspect, digital electrical signal waveform represents a combination oftwo waveforms having of different amplitudes. In one aspect, the waveshape is a trapezoid, a sine or cosine wave, a square wave, a trianglewave, or any combinations thereof. In one aspect, the digital electricalsignal waveform is a combined RF and ultrasonic signal waveformconfigured to maintain a predetermined ultrasonic frequency. In oneaspect, the first digital electrical signal waveform is a combined RFand ultrasonic waveform configured to deliver maximum power output.

According to various aspects, the electrical signal waveform also may beprovided to at least two surgical instruments 104, 106, 108simultaneously. The surgical instruments 104, 106, 108 may compriseinstruments that operate the same modalities or different modalities ofsurgical treatment techniques. In one aspect, the surgical instrumentsinclude at least one ultrasonic surgical instrument and at least one RFsurgical instrument.

With reference to FIG. 22 , in accordance with the method 1600, thedigital processing circuit instructs the DDS circuit 1300, 1400 to store1602 phase points or samples that define a digital electrical signalwaveform in a lookup table 1304, 1410 defined in the memory circuit. Thedigital electrical signal waveform is represented by a predeterminednumber of phase points that are stored in the lookup table 1304, 1410.The predetermined number of phase points define a predetermined waveshape. The DDS circuit 1300, 1400 receives 1604 a clock signal. At eachclock cycle, the DDS circuit 1300, 1400 retrieves 1606 a phase pointfrom the lookup table 1304, 1410 and provides the phase point (e.g.,sample) to the DAC circuit 1308, 1412. The DAC circuit 1308, 1412converts 1608 the phase point of the digital electrical signal waveforminto an analog electrical signal output (e.g., a sample/hold output ofthe DAC circuit 1308, 1412). The analog sample/hold output of the DACcircuit 1308, 1412 is filtered by the filter 1312, 1414 and amplified bya power amplifier 212, 326, 426, 506, for example, before the analogelectrical signal waveform is provided to the surgical instrument 104,106, 108.

The analog electrical signal waveform may be of a type that provides forthe application of a particular treatment modality for a surgicalinstrument connected to the generator. Accordingly, the analogelectrical signal waveform may be a RF waveform, an ultrasonic waveform,or a combination thereof. The analog electrical signal waveform may be acombined RF and ultrasonic waveform and the combined RF and ultrasonicwaveform may be configured to maintain a predetermined ultrasonicfrequency. In one aspect, the predetermined ultrasonic frequency is afrequency lock based on a surgical instrument 104, 106, 108 connected tothe generator 100. In another aspect, the analog electrical signalwaveform is a combined RF and ultrasonic waveform and the combined RFand ultrasonic waveform is configured to cause a surgical instrument104, 106, 108 to deliver a maximum power application of the surgicalinstrument 104, 106, 108 to tissue engaged with the surgical instrument104, 106, 108. The maximum power application may be based on the maximumpower output of a treatment modality of a surgical instrument 104, 106,108, such as, for example, an RF modality or an ultrasonic modality.According to further aspects, the analog electrical signal waveform maycomprise a high crest factor RF signal, a low crest factor RF signal, ora combination thereof and/or the electrical signal waveform may comprisea sine wave shape, a trapezoidal wave shape, a square wave shape, or acombination thereof. The analog electrical signal waveform may also beconfigured to provide a desired tissue effect or outcome to tissueengaged by a surgical instrument 104, 106, 108 when the analogelectrical signal waveform is received by the surgical instrument 104,106, 108. In one aspect, the desired tissue effect is at least one ofcutting, coagulation, or sealing.

The generator 100 also may be configured to switch between digital oranalog versions of multiple electrical signal waveforms. For example,the generator 100 may be configured to switch between a first electricalsignal waveform and a second electrical signal waveform based onpredetermined criteria, such as, for example, a desired tissue effectand/or feedback from a surgical instrument 104, 106, 108, which mayinclude measured values of a tissue parameter. The tissue parameter mayinclude a tissue type, a tissue amount, a tissue state, or a combinationthereof. Accordingly, the method 1600 includes storing a plurality ofelectrical signal waveforms in a plurality of lookup tables defined in amemory circuit. The electrical signal waveforms are represented by apredetermined number of phase points, wherein the phase points definepredetermined wave shapes based on desired tissue effects, tissueparameters, or other parameters associated with the surgical instrument104, 106, 108 connected to the generator 100.

Additionally, digital phase points of the digital electrical signalwaveform may be received by the generator 100 from a surgical instrument104, 106, 108 connected to the generator 100. The generator 100 mayreceive the phase points following or upon connection of the surgicalinstrument 104, 106, 108 to the generator 100. The phase points of thedigital electrical signal waveform may be stored in an EEPROM of thesurgical instrument 104, 106, 108, which is operable coupled to thegenerator 100 upon connection of the surgical instrument 104, 106, 108to the generator 100.

In accordance with the method 1600, the digital processing circuitreceives a feedback signal associated with tissue parameters. In oneaspect, based on the feedback signal the digital processing circuitswitches between the phase point of the first digital electrical signalwaveform and the phase point of the second digital electrical signalwaveform and the DAC circuit 1308, 1412 converts the retrieved phasepoint. In another aspect, based on the feedback signal the digitalprocessing circuit synchronizes the phase points of the first and seconddigital electrical signal waveforms to maximize power delivery per cycleand the DAC circuit 1308, 1412 circuit, the synchronized phase points.In one aspect, the first digital electrical signal waveform represents aRF waveform and the second digital electrical signal waveform representsan ultrasonic signal waveform.

With reference to FIG. 23 , in accordance with the method 1700, thedigital processing circuit instructs the DDS circuit 1300, 1400 to store1702 a first digital electrical signal waveform in a first lookup table1304, 1410 defined in the memory circuit. The first digital electricalsignal waveform is represented by a first predetermined number of phasepoints that are stored in the first lookup table 1304, 1410. The firstpredetermined number of phase points define a first wave shape. The DDScircuit 1300, 1400 receives 1704 a clock signal. At each clock cycle,the DDS circuit 1300, 1400 retrieves 1706 a phase point from the firstlookup table 1304, 1410.

In accordance with the method 1700, the digital processing circuit alsoinstructs the DDS circuit 1300, 1400 to store 1708 a second digitalelectrical signal waveform in a second lookup table 1304, 1410 definedin the memory circuit, or other memory circuit. The second digitalelectrical signal waveform is represented by a second predeterminednumber of phase points that are stored in the second lookup table 1304,1410. The second predetermined number of phase points define a secondwave shape. The DDS circuit 1300, 1400 receives 1710 a clock signal. Ateach clock cycle, the DDS circuit 1300, 1400 retrieves 1712 a phasepoint from the second lookup table 1304, 1410.

In accordance with the method 1700, the generator 100 or the surgicalinstrument 104, 106, 108 receives 1714 tissue parameter feedback fromsensors in the surgical instrument 104, 106, 108. The feedback mayprovide information regarding tissue impedance, tissue type, ortemperature of the tissue. In other aspects, the feedback may be basedon the temperature of the electrode or ultrasonic blade or electricalimpedance of the ultrasonic transducer, among other feedback parameters.Based on the tissue parameter feedback, the digital processing circuitdetermines 1716 whether to switch between the first and second phasepoints of the first and second electrical signal waveforms or whether tosynchronize the first and second phase points of the first and secondelectrical signal waveforms to maximize power delivery to the tissue percycle.

If the method 1700 proceeds along the “switch” branch, the digitalprocessing circuit switches 1718 between the phase point of the firstdigital electrical signal waveform and the phase point of the seconddigital electrical signal waveform during a tissue treatment procedure(e.g., “on-the-fly” or in virtual real time based on user or sensorinputs). The retrieved phase point of either the first or secondelectrical signal waveforms is provided to the DAC circuit 1308, 1412.The DAC circuit 1308, 1412 converts 1720 the retrieved phase point ofeither the first or second electrical signal waveforms to an analogelectrical signal. The sample/hold analog output of the DAC circuit1308, 1412 is filtered by the filter 1312, 1414 and amplified by a poweramplifier 212, 326, 426, 506, for example, before the analog electricalsignal waveform is provided to the surgical instrument 104, 106, 108.

If the method 1700 proceeds along the “synchronize” branch, the digitalprocessing circuit synchronizes 1722 the phase points of the first andsecond digital electrical signal waveforms to maximize power deliveryper cycle. The synchronized phase points of the first and second digitalelectrical signal waveforms are provided to the DAC circuit 1308, 1412.The DAC circuit 1308, 1412 converts 1724 the synchronized phase pointsof the first or second electrical signal waveforms to an analogelectrical signal. The analog sample/hold output of the DAC circuit1308, 1412 is filtered by the filter 1312, 1414 and amplified by a poweramplifier 212, 326, 426, 506, for example, before the analog electricalsignal waveform is provided to the surgical instrument 104, 106, 108.

In various aspects, the first and second electrical signal waveforms mayrepresent electrical signals having different wave shapes. In oneaspect, the first digital electrical signal waveform may represent an RFsignal suitable for driving an electrode of an electrosurgicalinstrument 106 or a multifunction surgical instrument 108 and the secondelectrical signal waveform may represent an ultrasonic signal fordriving an ultrasonic transducer of an ultrasonic instrument 104 or amultifunction surgical instrument 108. The first and second electricalsignal waveforms can be delivered separately, simultaneously,individually, or combined in one signal.

Examples of waveforms representing energy for delivery from a generatorare illustrated in FIGS. 24-28 . FIG. 24 illustrates an example graph1900 showing first and second individual waveforms representing a firstultrasonic output signal 1902 and a second ultrasonic output signal 1904superimposed on the same time and voltage scale for comparison purposes.The frequency of the first ultrasonic output signal 1902 is greater thanthe second ultrasonic output signal 1904. The first and secondultrasonic output signals 1902, 1904 are provided at the ENERGY outputof the generator 100. Time (t) is shown along the horizontal axis andvoltage (V) is shown along the vertical axis. The first ultrasonicoutput signal 1902 may have a frequency of about 50 kHz to about 100 kHzand a peak-to-peak voltage of ±1V. The second ultrasonic output signal604 has a frequency of about 20 kHz to 40 kHz and a peak-to-peak voltageof ±1V. It will be appreciated that the time (t) scale along thehorizontal axis and the voltage (V) scale along the vertical axis arenormalized for comparison purposes and may be different actualimplementations, or represent other electrical parameters such ascurrent. For comparison purposes, frequencies and amplitudes of thefirst and second ultrasonic output signals 1902, 1904 are not shown toscale. In other aspects, the frequency of the first ultrasonic outputsignal 1902 is the same as the frequency of the second ultrasonic outputsignal 1904. In one aspect, the first and second ultrasonic outputsignals 1902, 1904 may be combined as a sum as described in connectionwith FIG. 25 .

FIG. 25 illustrates an example graph 1910 showing the sum of the firstand second ultrasonic output signals 1902, 1904 shown in FIG. 24 . Time(t) is shown along the horizontal axis and voltage (V) is shown alongthe vertical axis. The sum of the first ultrasonic output signal 1902and the second ultrasonic output signal 1904 shown in FIG. 24 produces acombined output signal 1912 having a 2V peak-to-peak voltage, which istwice the amplitude of the original first and second ultrasonic outputsignals 1902, 1904 shown (1V peak-to-peak) shown in FIG. 24 . Anamplitude of twice the original amplitude can cause problems with theoutput section of the generator, such as distortion, saturation,clipping of the output, or stresses on the output components. Thus, themanagement of a single combined output signal 1912 that has multipletreatment components is an important aspect of the generator 500 shownin FIG. 8 . There are a variety of ways to achieve this management. Inone form, one of the first and second ultrasonic output signals 1902,1904 can be dependent on the peaks of the other output signal. In oneaspect, the first and second ultrasonic output signals 1902, 1904 may becombined with one or more than one RF output signals.

For example, FIG. 26 illustrates an example graph 1920 showing acombined output signal 1922 representative of a dependent sum of thefirst and second ultrasonic output signals 1902, 1904 shown in FIG. 24 .Time (t) is shown along the horizontal axis and voltage (V) is shownalong the vertical axis. As shown in FIG. 26 , the first ultrasonicoutput signal 1902 component of FIG. 24 depends on the peaks of thesecond ultrasonic output signal 1904 component of FIG. 24 such that theamplitude of the first ultrasonic output signal component of thedependent sum combined output signal 1922 is reduced when a peak of thesecond ultrasonic signal is anticipated. As shown in the example graph1920 in FIG. 26 , the peaks have been reduced from 2 to 1.5. In anotherform, one of the output signals is a function of the other outputsignal. As previously discussed, in one aspect, the combined outputsignal may comprise RF signal components as well as ultrasonic signalcomponents.

For example, FIG. 27 illustrates an example graph of an analog waveform1930 showing an output signal 1932 representative of a dependent sum ofthe first and second ultrasonic output signals 1902, 1904 shown in FIG.24 . Time (t) is shown along the horizontal axis and voltage (V) isshown along the vertical axis. As shown in FIG. 27 , the firstultrasonic output signal 1902 is a function of the second ultrasonicoutput signal 1904. This provides a hard limit on the amplitude of theoutput. As shown in FIG. 27 , the second ultrasonic output signal 1904is extractable as a sine wave while the first ultrasonic output signal1902 has distortion but not in a way to affect the coagulationperformance of the first ultrasonic output signal 1902.

A variety of other techniques can be used for compressing and/orlimiting the waveforms of the output signals. It should be noted thatthe integrity of the second ultrasonic output signal 1904 (FIG. 24 ) canbe more important than the integrity of the first ultrasonic outputsignal 1902 (FIG. 24 ) as long as the first ultrasonic output signal1902 has low frequency components for safe patient levels so as to avoidneuro-muscular stimulation. In another form, the frequency of anultrasonic waveform can be changed on a continuous basis in order tomanage the peaks of the waveform. Waveform control is important as morecomplex ultrasonic waveforms, such as a coagulation-type waveform 1942,as illustrated in the graph 1940 shown in FIG. 28 , are implemented withthe system. Again, time (t) is shown along the horizontal axis andvoltage (V) is shown along the vertical axis. The coagulation-typewaveform 1942 illustrated in FIG. 28 has a crest factor of 5.8, forexample.

FIG. 29 illustrates one cycle of a digital electrical signal waveform1950 of the analog waveform 1930 shown in FIG. 27 . The horizontal axisrepresents Time (t) and the vertical axis represents digital phasepoints. The digital electrical signal waveform 1950 is a digital versionof the desired analog waveform 1930 shown in FIG. 27 , for example. Thedigital electrical signal waveform 1950 is generated by storing a phasepoint 1952 that represents the amplitude at each clock cycle T_(clk)over one cycle or period T_(o). The digital electrical signal waveform1950 is generated over one period T_(o) by any suitable digitalprocessing circuit. The amplitude phase points are digital words storedin a memory circuit. In the example illustrated in FIG. 29 , the digitalword is a six-bit word that is capable of storing the amplitude phasepoints with a resolution of 2⁶ or 64 bits. It will be appreciated thatthe example shown in FIG. 29 is for illustrative purposes and in actualimplementations the resolution can be much higher. The digital amplitudephase points 1952 over one cycle T_(o) are stored in the memory as astring of string words in a lookup table 1304, 1410 as described inconnection with FIGS. 13 and 14 , for example. To generate the analogversion of the waveform 1930, the amplitude phase points 1952 are readsequentially from the memory from 0 to T_(o) at each clock cycle T_(clk)and are converted by a DAC circuit 1308, 1412, also described inconnection with FIGS. 13 and 14 . Additional cycles can be generated byrepeatedly reading the amplitude phase points 1952 of the digitalelectrical signal waveform 1950 the from 0 to T_(o) for as many cyclesor periods as may be desired. The smooth analog version of the waveform1930 (also shown in FIG. 27 ) is achieved by filtering the output of theDAC circuit 1308, 1412 by a filter 1312, 1414 (FIGS. 13 and 14 ). Thefiltered output 1314, 1422 (FIGS. 13 and 14 ) is applied to the input ofa power amplifier 212, 326, 426, 506 (FIGS. 5-8 ).

A variety of techniques can be used for compressing and/or limitingultrasonic electrical signal waveforms. It should be noted that theintegrity of an ultrasonic electrical signal waveform can be moreimportant than the integrity of the RF electrical signal waveform aslong as any low frequency components of the RF electrical signalwaveform are limited to safe patient levels so as to avoidneuro-muscular stimulation. In another form, the frequency of an RFelectrical signal waveform can be changed on a continuous basis in orderto manage the peaks of the waveform. Waveform control is important asmore complex RF waveforms, are implemented with the system.

The surgical instruments 104, 106, 108 described herein can includefeatures to allow the energy being delivered by the generator 100 to bedynamically changed based on the type of tissue being treated by the endeffector 122, 124, 125 of the surgical instrument 104, 106, 108 andvarious characteristics of the tissue. In one aspect, an algorithm forcontrolling the power output from a generator 100 that is delivered tothe end effector 122, 124, 125 of the surgical instrument 104, 106, 108can include an input that represents the tissue type to allow the energyprofile from the generator 100 to be dynamically changed during theprocedure based on the type of tissue being effected by the end effector122, 124, 125 of the surgical instrument 104, 106, 108.

FIGS. 30 and 31 are logic flow diagrams of methods 2000, 2100 ofgenerating an electrical signal waveform by any of the generators 100,200, 300, 400, 500, 9001, 1003, 1103, 1203 described herein. Forconciseness and clarity the generators 100, 200, 300, 400, 500, 9001,1003, 1103, 1203 will be referred to generally as the generator 100. Themethod 1500 will be described with reference to FIGS. 1, 13, 14, and 29and FIGS. 5-8 . In accordance with the methods 2000, 2100 describedherein, the generator 100 is configured to generate one or more than oneultrasonic electrical signal waveform to drive the ultrasonic transducer120 of at least two surgical instruments 104, 108 simultaneously or todrive two ultrasonic transducers 120 in one surgical instrument 104, 108simultaneously. The surgical instruments 104, 108 may compriseinstruments that operate the same modalities or different modalities ofsurgical treatment techniques. In one aspect, the surgical instruments104, 108 comprise at least one ultrasonic transducer 120. Nevertheless,each surgical instrument 104, 108 may comprise multiple ultrasonictransducer 120. The ultrasonic transducer(s) 120 in each of the surgicalinstruments 104, 108 may be driven by a signal of different frequencies,voltages, and/or currents. For example, the ultrasonic transducer 120 ofthe ultrasonic surgical instrument 104 may be driven at a frequency of55.5 kHz and the ultrasonic transducer 120 of the multifunction surgicalinstrument 108 may be driven at a frequency of 33 kHz. Generally, theultrasonic transducer 120 can be driven at frequencies in excess of 20kHz up to 100 kHz.

In accordance with the methods 2000, 2100, the generator 100 comprises adigital processing circuit, a DDS circuit 1300, 1400, a memory circuitdefining a lookup table 1304, 1410, and DAC circuit 1308, 1412, asdescribed herein. The digital processing circuit may comprise anydigital processing circuit, microprocessor, microcontroller, digitalsignal processor, logic device comprising combinational logic orsequential logic circuits, or any suitable digital circuit. The memorycircuit may be located either in the surgical instrument 104, 108 or thegenerator 100. In one aspect, the DDS circuit 1300, 1400 is coupled tothe digital processing circuit and the memory circuit. In anotheraspect, the memory circuit is part of the DDS circuit 1300, 1400.

In various aspects, the generator 100 may be configured to drivemultiple ultrasonic transducers 120 in one or more ultrasonic surgicalinstruments 104, 108 simultaneously. Thus the generator 100 may beconfigured to drive the surgical instruments 104, 108 in multiplevibration modes to achieve a longer active length at the ultrasonicblade 128, 149 and to create different tissue effects.

According to one of the present disclosure, the generator 100 may beconfigured to provide ultrasonic electrical signal waveforms defining anumber of wave shapes to a surgical instrument 104, 108 so that thesurgical instrument 104, 108 may apply a desired therapy to tissue atthe end effector 122, 125.

In one aspect, the generator 100 may be configured to generate a digitalelectrical signal waveform such that the desired wave shape can bedigitized by a number of phase points or samples which are stored in alookup table 1304, 1410 defined in volatile or non-volatile memory asdiscussed above in connection with FIGS. 13 and 14 , for example. Thephase points or samples may be stored in the lookup table 1304, 1410defined in a FPGA, for example. The wave shape may be digitized into anumber of phase points or samples as shown in TABLE 1. In one aspect,the wave shape may be digitized into 1024 phase points, for example. Thedigital processing circuit of the generator 100 may control by softwareor digital control the FPGA to scan the addresses in the lookup tablewhich in turn provides varying digital input values to the DAC circuit1308, 1412 that feeds a power amplifier 1062, 422, 506. The addressesmay be scanned according to a frequency of interest. Using such thelookup table 1304, 1410 enables generating various types of wave shapesthat can be used to drive the ultrasonic transducers 120 of the surgicalinstruments 104, 108 simultaneously. Furthermore, multiple wave shapelookup tables 1304, 1410 can be created, stored, and applied to tissuefor a single generator 100.

In one aspect, the electrical signal waveforms may be defined by anoutput current, an output voltage, an output power, or frequencysuitable to drive the ultrasonic transducer 120 or multiple ultrasonictransducers (e.g. two or more ultrasonic transducers). In the case ofthe multifunction surgical instrument 108, in addition to driving theultrasonic transducer 120, the electrical signal waveforms may bedefined by an output current, an output voltage, an output power, orfrequency suitable to drive the electrodes located in the end effector125 of the multifunction surgical instrument 108.

Further, in one aspect where the surgical instrument 104, 108 comprisesultrasonic components, the electrical signal waveform may be configuredto drive at least two vibration modes of the ultrasonic transducer 120.Accordingly, a generator 100 may be configured to provide a electricalsignal waveform to at least one surgical instrument 104, 108 wherein theelectrical signal waveform defines at least one wave shape selected outof a plurality of wave shapes stored in the lookup table 1304, 1410.Further, the electrical signal waveform provided to the two surgicalinstruments 104, 108 may define two or more wave shapes. The lookuptable 1304, 1410 may comprise information associated with a plurality ofwave shapes and the lookup table 1304, 1410 may be stored in a memorylocated either in the generator 100 or the surgical instruments 104,108. In one embodiment or example, the lookup table 1304, 1410 may be adirect digital synthesis table, which may be stored in an FPGA locatedin the generator 100 or the surgical instruments 104, 108. The lookuptable 1304, 1410 may be addressed using any suitable technique forcategorizing wave shapes. According to one aspect, the DDS lookup table1304, 1410 may be addressed according to the frequency of the electricalsignal waveform. Additional information associated with the plurality ofwave shapes also may be stored as digital information in the DDS lookuptable 1304, 1410.

In one aspect, the generator 100 may comprise a DAC circuit 1308, 1412and a power amplifier 1062, 422, 506. The DAC circuit 1308, 1412 iscoupled to the power amplifier 212, 326, 426, 506 such that the DACcircuit 1308, 1412 provides the analog electrical signal waveform to afilter 1312, 1414 and the output of the filter 1312, 1414 is provided tothe power amplifier 1062, 422, 506. The output of the power amplifier isprovided to the surgical instrument 104, 108.

Further, in one aspect the generator 100 may be configured to providethe electrical signal waveform to at least two surgical instruments 104,108 simultaneously. This may be accomplished through a single outputport or channel of the generator 100. The generator 100 also may beconfigured to provide the electrical signal waveform, which may definetwo or more wave shapes, via a single output port or channel to the twosurgical instruments 104, 108 simultaneously. The analog signal outputof the generator 100 may define multiple wave shapes to one or more thanone surgical instruments 104, 108. For example, in one aspect, theelectrical signal waveform comprises multiple ultrasonic drive signals.In another aspect, the electrical signal waveform comprises multipleultrasonic drive signals and one or more than one RF signals.Accordingly, an electrical signal waveform output of the generator 100may comprise multiple ultrasonic drive signals, multiple RF signals,and/or a combination of multiple ultrasonic drive signals and a RFsignals.

In one aspect, the generator 100 as described herein may allow for thecreation of various types of direct digital synthesis lookup tables1304, 1410 within an FPGA located in the generator 100. Some examples ofthe wave shapes that may be produced by the generator 100 include highcrest factor signals (which may be used for surface coagulation), lowcrest factor signals (which may be used for deeper tissue penetration),and electrical signal waveforms that promote efficient touch-upcoagulation. The generator 100 also may create multiple wave shapelookup tables 1304, 1410. The generator 100 can be configured to switchbetween different electrical signal waveforms for driving ultrasonictransducers 120 during a procedure (e.g., “on-the-fly” or in virtualreal time based on user or sensor inputs) based on desired tissueeffects or feedback signals associated with the state of the tissuelocated in the end effector 122, 125. Switching may be based on tissueimpedance, tissue temperature, state of coagulation, state ofdissection, and/or other factors.

In one aspect, the generator 100 as described herein also may provide,in addition to the traditional sine wave shape, wave shapes thatmaximizes the power into tissue per cycle (i.e. trapezoidal, square, ortriangular wave shapes). It also may provide wave shapes that aresynchronized in a manner that would maximize power delivery in the caseof an electrical signal waveform comprises RF and ultrasonic signalcomponents to drive ultrasonic and RF therapeutic energy simultaneouslywhile maintaining ultrasonic frequency lock. Further, custom wave shapesspecific to various types of surgical instruments 104, 108 and theirtissue effects can be stored in a lookup table 1304, 1410 memory locatedin the generator 100 or the surgical instrument 104, 108, where thememory may be a volatile (RAM) or non-volatile (EEPROM) memory. The waveshape may be fetched from the lookup table 1304, 1410 memory uponconnecting the surgical instrument 104, 108 to the generator 100.

With reference to FIG. 30 , in accordance with the method 2000, thedigital processing circuit instructs the DDS circuit 1300, 1400 to store2002 a first digital electrical signal waveform in a first lookup table1304, 1410 defined in the memory circuit. The first digital electricalsignal waveform is represented by a first predetermined number of phasepoints or samples that are stored in the first lookup table 1304, 1410.The first predetermined number of phase points define a first waveshape. The DDS circuit 1300, 1400 receives 2004 a clock signal. At eachclock cycle, the DDS circuit 1300, 1400 retrieves 1506 a phase pointfrom the first lookup table 1304, 1410. In one aspect, the first digitalelectrical signal waveform is a digital version of a first ultrasonicelectrical signal waveform.

Further, in accordance with the method 2000, the digital processingcircuit also instructs the DDS circuit 1300, 1400 to store 2008 a seconddigital electrical signal waveform in a second lookup table 1304, 1410defined in the memory circuit, or other memory circuit. The seconddigital electrical signal waveform is represented by a secondpredetermined number of phase points that are stored in the secondlookup table 1304, 1410. The second predetermined number of phase pointsdefine a second wave shape. The DDS circuit 1300, 1400 receives 2010 aclock signal. At each clock cycle, the DDS circuit 1300, 1400 retrieves2012 a phase point from the second lookup table 1304, 1410. In oneaspect, the second digital electrical signal waveform represents asecond ultrasonic electrical signal waveform.

The digital signal processing circuit combines 2014 the retrieved phasepoint of the first digital electrical signal waveform and the retrievedphase point of the second digital electrical signal waveform to form acombined digital phase point. The combined digital phase point of theelectrical signal waveform is converted 2016 by a DAC circuit 1308, 1412to a combined analog signal. The analog signal 1310, 1420 output of theDAC circuit 1308, 1412 is filtered 2018 by a filter 1312, 1414 and isamplified 2020 by a power amplifier 212, 326, 426, 506 before thecombined analog electrical signal waveform is provided to a surgicalinstrument 104, 108 connected to the generator 100. The first and seconddigital electrical signal waveforms may be combined in a way, forexample using an appropriate algorithm, which is specifically designedto provide a proper input to a surgical instrument 104, 108. This mayinclude limiting peaks of the combined digital electrical signalwaveform so that the surgical instrument 104, 108 and/or components ofthe generator 100 are not damaged. Damage is one consequence ofoverdriving the components, however, another consequence is undesiredwave shapes that can affect the ultrasonic transducer 120 or causeundesired output, such as unintended frequency components, on the RFpoles. Accordingly, in one aspect, the output components are not damagedbut are operating in a non-linear fashion and produce undesirable waveshapes, distortions, or harmonic components that could affect theoperation of the ultrasonic transducer 120 or be delivered to tissuethrough the RF electrodes.

In one aspect, the combined analog electrical signal waveform isconfigured to drive a plurality of ultrasonic transducers 120, eithersimultaneously or sequentially. In another aspect, the combined analogelectrical signal waveform is configured to drive a plurality ofultrasonic operational modes of an ultrasonic surgical instrument 104,108. In one aspect, the ultrasonic surgical instrument 104, 108comprises an ultrasonic transducer 120 and an ultrasonic blade 128, 149.The combined analog electrical signal waveform may be configured todrive the ultrasonic transducer 120 to produce a predetermined activelength of the ultrasonic blade 128, 149. In one aspect, the combinedanalog electrical signal waveform may be configured to drive theultrasonic transducer 120 to produce a predetermined tissue effect bythe ultrasonic blade 128, 149.

In one aspect, the first and second digital electrical signal waveformsrepresent first and second digital ultrasonic electrical signalwaveforms and the method 2000 further comprises combining a RFelectrical signal waveform with the first and second ultrasonicelectrical signal waveforms.

In one aspect, the digital processing circuit stores phase points of adigital electrical signal waveform in the lookup table 1304, 1410defined by the memory circuit. The digital processing circuit storesphase points of multiple digital electrical signal waveforms incorresponding multiple lookup tables 1304, 1410 defined by the memorycircuit or other memory circuits. Each of the digital electrical signalwaveforms is represented by a predetermined number of phase points. Eachof the predetermined number of phase points defines a different waveshape.

In one aspect, the digital processing circuit receives a feedback signalassociated with tissue parameters and modifying the predetermined waveshape according to the feedback signal.

In one aspect, the digital electrical signal waveform represents acombination of two waveforms having different amplitudes. In one aspect,the digital electrical signal waveform represents a combination of twowaveforms having different frequencies. In one aspect, the digitalelectrical signal waveform represents a combination of two waveformshaving of different amplitudes. In one aspect, the wave shape is atrapezoid, a sine or cosine wave, a square wave, a triangle wave, or anycombinations thereof. In one aspect, the combined digital signalwaveform is configured to maintain a predetermined ultrasonic frequency.In one aspect, the combined digital signal waveform is configured todeliver maximum power output.

With reference to FIG. 31 , in accordance with the method 2100, thegenerator 100 generate 2102 a first digital ultrasonic electrical signalwaveform, generates 2104 a second digital ultrasonic electrical signalwaveform, and combines 2106 the first and second digital ultrasonicelectrical signal waveforms. The DAC circuit 1308, 1412 converts 2108the combined digital ultrasonic electrical signal waveform into ananalog signal. The analog signal is delivered 2110 to a surgicalinstrument 104, 108 connected to the generator 100. The ultrasonicelectrical signal waveform is configured to apply voltage, current, orpower associated to an ultrasonic transducer 120 of a surgicalinstrument 104, 108 configured to receive the ultrasonic electricalsignal waveform. In one aspect, each of the surgical instruments 104,108 may comprise a plurality of ultrasonic transducers 120.

A digitized ultrasonic electrical signal waveform, including a combineddigital ultrasonic electrical signal waveform may be stored in a memorycircuit defining a lookup table 1304, 1410 located either in thegenerator 100 or the surgical instrument 104, 106. The lookup table1304, 1410 may be a direct digital synthesis table, located in thegenerator 100. The ultrasonic electrical signal waveform(s) and/or thecombined ultrasonic electrical signal waveform(s) may consist of aplurality of phase points or samples stored in the memory circuit. Inorder for the generator 100 to output an analog ultrasonic electricalsignal waveform made by combining two or more ultrasonic electricalsignal waveforms, or other ultrasonic electrical signal waveform, thephase points are retrieved from the memory circuit by a digitalprocessing circuit associated with the generator 100 or the surgicalinstrument 104, 108. As previously discussed, the phase points definethe digital combined ultrasonic electrical signal waveform. The phasepoints are retrieved from the memory circuit upon connection of thesurgical instrument 104, 108 to the generator 100. The phase points ordigital samples may comprise at least 1,024 phase points. In otheraspects the digital samples may comprise any number of phase points asshown in TABLE 1. Further, the analog version of the combined ultrasonicelectrical signal waveform may be output to a surgical instrument 104,108 via a single port of the generator 100 through which the surgicalinstrument 104, 108 is connected to the generator 100.

In one aspect, the generator 100, as described herein, may be a singleport or multiple port system and may include an output transformer withmultiple taps to provide the power in the form that is required for thetreatment. In one aspect, the form may be higher voltage and lowercurrent, in order to drive an ultrasonic transducer 120. In anotheraspect, the form may be lower voltage and higher current to drive vesselsealing electrodes. Or it may be a coagulation or type waveform fortouch-up or spot coagulation.

In addition, the generator 100 may comprise a FPGA. The generator 100may be configured to scan, via the FPGA, a lookup table 1304, 1410comprising samples the digital electrical signal waveform, retrieve, viathe FPGA, the stored phase points from the lookup table 1304, 1410, andprovide the phase points to a DAC circuit 1308, 1412. The analog signal1310, 1420 output of the DAC circuit 1308, 1412 is filtered by a filter1312, 1414, and amplified by a power amplifier 1062, 422, 506. Theamplified analog ultrasonic electrical signal waveform is then outputfrom the generator 100 to the surgical instrument 104, 108.

The analog ultrasonic electrical signal waveform may be configured for aparticular treatment modality of the surgical instrument 104, 108connected to the generator 100. Accordingly, the ultrasonic electricalsignal waveform may be a single or composite ultrasonic electricalsignal waveform. In one aspect, the ultrasonic electrical signalwaveform or the composite ultrasonic electrical signal waveform may becombined with a RF waveform, which may be provided to at least twosurgical instruments 104, 108 simultaneously. The surgical instruments104, 108 may comprise instruments that operate in the same modalities ordifferent modalities of surgical treatment techniques. In one aspect,the surgical instruments 104, 108 include at least one ultrasonicsurgical instrument 104 and at least one combination RFelectrosurgical/ultrasonic surgical instrument. The electrical signalwaveform also may be a combined RF and ultrasonic electrical signalwaveform configured to maintain a predetermined ultrasonic frequency. Inone aspect, the predetermined ultrasonic frequency is frequency lockedwhen the surgical instrument 104, 108 is connected to the generator 100.In another aspect, the combined RF and ultrasonic electrical signalwaveform is configured to cause the surgical instrument 104, 108 todeliver maximum power to the tissue engaged in the end effector 122, 125of the surgical instrument 104, 108. The maximum power application maybe based on the maximum power output of a treatment modality of asurgical instrument 104, 108, such as, for example, an RF modalityand/or an ultrasonic modality. According to further aspects, theelectrical signal waveform may comprise a high crest factor signal, alow crest factor signal, or a combination thereof and/or the electricalsignal waveform may comprise a sine wave shape, a trapezoidal waveshape, a square wave shape, a triangular wave shape, or a combinationthereof. The electrical signal waveform also may be configured toprovide a desired tissue effect or outcome to tissue engaged by the endeffector 122, 125 of the surgical instrument 104, 108 when theelectrical signal waveform is received by the surgical instrument 104,108. In one aspect, the desired tissue effect is at least one ofcutting, coagulation, and/or sealing.

The generator 100 also may be configured to switch between a firstelectrical signal waveform and a second electrical signal waveform basedon predetermined criteria, such as, for example, a desired tissue effectand/or feedback from a surgical instrument 104, 108, which may includemeasured values of a tissue parameter. The tissue parameter may includea tissue type, a tissue amount, a tissue state, or a combinationthereof. Accordingly, the methods described above also may includedelivering the first electrical signal waveform and the secondelectrical signal waveform based on a desired tissue effect, tissueparameter, and/or other parameters associated with a surgical instrument104, 108 connected to the generator 100.

Additionally, the first and second digital electrical signal waveformsstored in the generator 100 may be received by the generator 100 from asurgical instrument 104, 108 connected to the generator 100. Thegenerator 100 may receive the first and second digital electrical signalwaveforms following or upon connecting the surgical instrument 104, 108to the generator 100. The samples of the first and second digitalelectrical signal waveforms may be stored in an EEPROM of the surgicalinstrument 104, 108, which is operable coupled to the generator 100 uponconnection of the surgical instrument 104, 108 to the generator 100.

FIGS. 32-34 are logic flow diagrams of methods 2200, 2300, 2400 ofgenerating an electrical signal waveform configured to drive surgicalinstruments and to protect output components of any of the generators100, 200, 300, 400, 500, 9001, 1003, 1103, 1203 described herein. Forconciseness and clarity, the generators 100, 200, 300, 400, 500, 9001,1003, 1103, 1203 will be referred to as the generator 100. Accordingly,the generator 100 is representative of the generators 200, 300, 400,500, 9001, 1003, 1103, 1203 described herein. The method 1500 will bedescribed with reference to FIGS. 1, 13, 14, and 20 and with referenceto the generator circuits described in connection with FIGS. 5-8 . Thegenerator 100 comprises a digital processing circuit, a DDS circuit1300, 1400, a memory circuit defining a lookup table 1304, 1410, and DACcircuit 1308, 1412, as described herein. The digital processing circuitmay comprise any digital processing circuit, microprocessor,microcontroller, digital signal processor, logic device comprisingcombinational logic or sequential logic circuits, or any suitabledigital circuit. The memory circuit may be located either in thesurgical instrument 104, 106, 108 or the generator 100. In one aspect,the DDS circuit 1300, 1400 is coupled to the digital processing circuitand the memory circuit. In another aspect, the memory circuit is part ofthe DDS circuit 1300, 1400.

In accordance with the methods 2200, 2300, 2400 the digital processingcircuit instructs the DDS circuit 1300, 1400 to store phase points orsamples that define a digital electrical signal waveform in a lookuptable 1304, 1410 defined in the memory circuit. The digital electricalsignal waveform is represented by a predetermined number of phase pointsthat are stored in the lookup table 1304, 1410. The predetermined numberof phase points define a predetermined wave shape. The DDS circuit 1300,1400 receives a clock signal. At each clock cycle, the DDS circuit 1300,1400 retrieves a phase point from the lookup table 1304, 1410 andprovides the phase point (e.g., sample) to the DAC circuit 1308, 1412.The DAC circuit 1308, 1412 converts the phase point of the digitalelectrical signal waveform into an analog electrical signal output(e.g., a sample/hold output of the DAC circuit 1308, 1412). The analogsample/hold output of the DAC circuit 1308, 1412 is filtered by thefilter 1312, 1414 and amplified by a power amplifier 212, 326, 426, 506(FIGS. 5-8 ), for example, before the analog electrical signal waveformis provided to the surgical instrument 104, 106, 108.

The one or more than one digital electrical signal waveforms may begenerated from a one or more than one lookup tables 1304, 1410 asdescribed in connection with FIGS. 13 and 14 . The one or more than onedigital electrical signal waveform may be defined by a plurality of waveshapes that are combined to form a complex waveform. The lookup tables1304, 1410 may be defined in a memory circuit in communication with adigital processing circuit of the generator 100 or the surgicalinstrument 104, 106, 108. In one aspect, the lookup tables 1304, 1410may be DDS lookup tables that can be addressed according to a desiredfrequency of the electrical signal waveforms. In one aspect, the digitalelectrical signal waveform is a combination of at least two wave shapes.The combined digital electrical signal waveform is provided to the DACcircuit 1308, 1410 and may be filtered by the filter 1312, 1414 andamplified by a power amplifier. The combined analog electrical signalwaveform may be an ultrasonic drive signal having a frequency of 55 kHzor an RF signal having a frequency of 330 kHz or a combination of theultrasonic drive signal and the RF signal.

Additionally, digital phase points of the digital electrical signalwaveform may be received by the generator 100 from a surgical instrument104, 106, 108 connected to the generator 100. The generator 100 mayreceive the phase points following or upon connection of the surgicalinstrument 104, 106, 108 to the generator 100. The phase points of thedigital electrical signal waveform may be stored in an EEPROM of thesurgical instrument 104, 106, 108, which is operable coupled to thegenerator 100 upon connection of the surgical instrument 104, 106, 108to the generator 100.

According to various aspects, the electrical signal waveform also may beprovided to at least two surgical instruments 104, 106, 108simultaneously. The surgical instruments 104, 106, 108 may compriseinstruments that operate the same modalities or different modalities ofsurgical treatment techniques. In one aspect, the surgical instrumentsinclude at least one ultrasonic surgical instrument and at least one RFsurgical instrument.

In various aspects, the electrical signal waveforms may representelectrical signals having different wave shapes. In one aspect, theelectrical signal waveforms may represent ultrasonic signals suitablefor driving ultrasonic transducers 120 of an ultrasonic surgicalinstrument 104, RF signals suitable for driving an electrode of anelectrosurgical instrument 106 or a multifunction surgical instrument108. A plurality of the electrical signal waveforms can be deliveredseparately, simultaneously, individually, or combined in one signal.

With reference now to FIG. 32 , in accordance with the method 2200, thegenerator 100 is configured to generate 2202 a first digital electricalsignal waveform, generate 2204 a second digital electrical signalwaveform, combine 2206 the first and second digital electrical signalwaveform, and modify 2208 the combined digital electrical signalwaveform to form a modified digital electrical signal waveform. A peakamplitude of the modified digital electrical signal waveform isconfigured not to exceed a predetermined value such that the amplituderemains within the normal operating rating of the amplifier 212, 326,426, 506 and other output components of the generator 100. The modifieddigital electrical signal waveform is converted to an analog electricalsignal waveform by the DAC circuit 1308, 1412, which is then applied tothe amplifier 212, 326, 426, 506 and other output components of thegenerator 100. The analog electrical signal waveform is delivered to atleast one surgical instrument 104, 106, 108 connected to the generator100. The first digital electrical signal waveform and/or the seconddigital electrical signal waveform may be extractable from the combineddigital electrical signal waveform. Further, either the first or thesecond digital electrical signal waveform may comprise an arbitraryfunction, a sine wave function, a square wave function, a triangularfunction, which are extractable from the combined digital electricalsignal waveform. In one aspect, the second digital electrical signalwaveform is an RF waveform and/or the first digital electrical signalwaveform is an ultrasonic waveform.

The first digital electrical signal waveform may include a RF drivesignal and the second digital electrical signal waveform may include anultrasonic drive signal. The first and/or the second digital electricalsignal waveform may be generated via the DDS circuit 1300, 1400 of thegenerator 100. In one aspect, the method 1500 further comprisesdetermining that the peak maximum amplitude of the combined digitalelectrical signal waveform is approaching as the combined digitalelectrical signal waveform is being delivered or transmitted to thesurgical instrument 104, 106, 108. In another aspect, the method 2200further comprises determining a peak amplitude of the combined digitalelectrical signal waveform and modifying the combined digital electricalsignal waveform based on the peak amplitude of the combined waveform. Inaddition, the generator 100 may be configured to modify the combineddigital electrical signal waveform by reducing the amplitude of thecombined digital electrical signal waveform upon determining that thepeak amplitude of the combined digital electrical signal waveform isapproaching during transmission or delivery of the analog electricalsignal waveform to the surgical instrument 104, 106, 108.

With reference now to FIG. 33 , in accordance with the method 2300, thegenerator 100 is configured to generate 2302 a first digital electricalsignal waveform, generate 2304 a second digital electrical signalwaveform, where the second digital electrical signal waveform is afunction of the first digital electrical signal waveform. The generator100 is configured to combine 2306 the first digital electrical signalwaveform and the second digital electrical signal waveform to form acombined digital electrical signal waveform. The peak amplitude of thecombined digital electrical signal waveform is configured not to exceeda predetermined value such that the amplitude remains within the normaloperating rating of the amplifier 212, 326, 426, 506 and other outputcomponents of the generator 100. The generator 100 is configured todeliver 2308 the combined digital electrical signal waveform to at leastone surgical instrument 104, 106, 108 connected to the generator 100.The first digital electrical signal waveform and/or the second digitalelectrical signal waveform may be extractable from the combined digitalelectrical signal waveform. Further, either the first or the seconddigital electrical signal waveform may comprise an arbitrary function, asine wave function, a square wave function, a triangular function, whichare extractable from the combined digital electrical signal waveform. Inone aspect, the second digital electrical signal waveform is an RFwaveform and/or the first digital electrical signal waveform is anultrasonic waveform.

With reference now to FIG. 34 , in accordance with the method 2400, thegenerator 100 is configured to generate 2402 a first digital electricalsignal waveform, generate 2404 a second digital electrical signalwaveform, where the second digital electrical signal waveform is afunction of the first digital electrical signal waveform. The generator100 is configured to modify 2404 a frequency of the first digitalelectrical signal waveform to form a frequency modified first digitalelectrical signal waveform. The generator 100 is configured to combine2406 the frequency modified first digital electrical signal waveform andthe second digital electrical signal waveform to form a combined digitalelectrical signal waveform. The generator 100 is configured to deliver2408 the combined digital electrical signal waveform to at least onesurgical instrument 104, 106, 108 connected to the generator 100. Thecombined digital electrical signal waveform may be configured such thata peak amplitude of the combined waveform does not exceed apredetermined value such that amplitude remains within the safeoperating rating of the amplifier 212, 326, 426, 506 and other outputcomponents of the generator 100. The first digital electrical signalwaveform and/or the second digital electrical signal waveform may beextractable from the combined digital electrical signal waveform.Further, either the first or the second digital electrical signalwaveform may comprise an arbitrary function, a sine wave function, asquare wave function, a triangular function, which are extractable fromthe combined digital electrical signal waveform. In one aspect, thesecond digital electrical signal waveform is an RF waveform and/or thefirst digital electrical signal waveform is an ultrasonic waveform.

In various aspects, the first and second electrical signal waveforms mayrepresent electrical signals having different wave shapes. In oneaspect, the first digital electrical signal waveform may represent an RFsignal suitable for driving an electrode of an RF electrosurgicalinstrument 106 or a multifunction surgical instrument 108 and the secondelectrical signal waveform may represent an ultrasonic signal fordriving an ultrasonic transducer of an ultrasonic surgical instrument104 or a multifunction surgical instrument 108. The first and secondelectrical signal waveforms can be delivered separately, simultaneously,individually, or combined in one signal.

While the examples herein are described mainly in the context ofelectrosurgical instruments, it should be understood that the teachingsherein may be readily applied to a variety of other types of medicalinstruments. By way of example only, the teachings herein may be readilyapplied to tissue graspers, tissue retrieval pouch deployinginstruments, surgical staplers, ultrasonic surgical instruments, etc. Itshould also be understood that the teachings herein may be readilyapplied to any of the instruments described in any of the referencescited herein, such that the teachings herein may be readily combinedwith the teachings of any of the references cited herein in numerousways. Other types of instruments into which the teachings herein may beincorporated will be apparent to those of ordinary skill in the art.

It should be appreciated that any patent, publication, or otherdisclosure material, in whole or in part, that is said to beincorporated by reference herein is incorporated herein only to theextent that the incorporated material does not conflict with existingdefinitions, statements, or other disclosure material set forth in thisdisclosure. As such, and to the extent necessary, the disclosure asexplicitly set forth herein supersedes any conflicting materialincorporated herein by reference. Any material, or portion thereof, thatis said to be incorporated by reference herein, but which conflicts withexisting definitions, statements, or other disclosure material set forthherein will only be incorporated to the extent that no conflict arisesbetween that incorporated material and the existing disclosure material.

Aspects of the present disclosure have application in conventionalendoscopic and open surgical instrumentation as well as application inrobotic-assisted surgery. For instance, those of ordinary skill in theart will recognize that various teaching herein may be readily combinedwith various teachings of U.S. Pat. No. 6,783,524, titled ROBOTICSURGICAL TOOL WITH ULTRASOUND CAUTERIZING AND CUTTING INSTRUMENT,published Aug. 31, 2004, the disclosure of which is incorporated byreference herein.

Aspects of the devices disclosed herein can be designed to be disposedof after a single use, or they can be designed to be used multipletimes. Various aspects may, in either or both cases, be reconditionedfor reuse after at least one use. Reconditioning may include anycombination of the steps of disassembly of the device, followed bycleaning or replacement of particular pieces, and subsequent reassembly.In particular, aspects of the device may be disassembled, and any numberof the particular pieces or parts of the device may be selectivelyreplaced or removed in any combination. Upon cleaning and/or replacementof particular parts, aspects of the device may be reassembled forsubsequent use either at a reconditioning facility, or by a surgicalteam immediately prior to a surgical procedure. Those skilled in the artwill appreciate that reconditioning of a device may utilize a variety oftechniques for disassembly, cleaning/replacement, and reassembly. Use ofsuch techniques, and the resulting reconditioned device, are all withinthe scope of the present application.

By way of example only, aspects described herein may be processed beforesurgery. First, a new or used instrument may be obtained and ifnecessary cleaned. The instrument may then be sterilized. In onesterilization technique, the instrument is placed in a closed and sealedcontainer, such as a plastic or TYVEK bag. The container and instrumentmay then be placed in a field of radiation that can penetrate thecontainer, such as gamma radiation, x-rays, or high-energy electrons.The radiation may kill bacteria on the instrument and in the container.The sterilized instrument may then be stored in the sterile container.The sealed container may keep the instrument sterile until it is openedin a medical facility. A device may also be sterilized using any othertechnique known in the art, including but not limited to beta or gammaradiation, ethylene oxide, or steam.

Having shown and described various aspects of the present disclosure,further adaptations of the methods and systems described herein may beaccomplished by appropriate modifications by one of ordinary skill inthe art without departing from the scope of the present disclosure.Several of such potential modifications have been mentioned, and otherswill be apparent to those skilled in the art. For instance, theexamples, aspects, geometrics, materials, dimensions, ratios, steps, andthe like discussed above are illustrative and are not required.Accordingly, the scope of the present disclosure should be considered interms of the following claims and is understood not to be limited to thedetails of structure and operation shown and described in thespecification and drawings.

While various details have been set forth in the foregoing description,it will be appreciated that the various aspects of the techniques foroperating a generator for digitally generating electrical signalwaveforms and surgical instruments may be practiced without thesespecific details. One skilled in the art will recognize that the hereindescribed components (e.g., operations), devices, objects, and thediscussion accompanying them are used as examples for the sake ofconceptual clarity and that various configuration modifications arecontemplated. Consequently, as used herein, the specific exemplars setforth and the accompanying discussion are intended to be representativeof their more general classes. In general, use of any specific exemplaris intended to be representative of its class, and the non-inclusion ofspecific components (e.g., operations), devices, and objects should notbe taken limiting.

Further, while several forms have been illustrated and described, it isnot the intention of the applicant to restrict or limit the scope of theappended claims to such detail. Numerous modifications, variations,changes, substitutions, combinations, and equivalents to those forms maybe implemented and will occur to those skilled in the art withoutdeparting from the scope of the present disclosure. Moreover, thestructure of each element associated with the described forms can bealternatively described as a means for providing the function performedby the element. Also, where materials are disclosed for certaincomponents, other materials may be used. It is therefore to beunderstood that the foregoing description and the appended claims areintended to cover all such modifications, combinations, and variationsas falling within the scope of the disclosed forms. The appended claimsare intended to cover all such modifications, variations, changes,substitutions, modifications, and equivalents.

For conciseness and clarity of disclosure, selected aspects of theforegoing disclosure have been shown in block diagram form rather thanin detail. Some portions of the detailed descriptions provided hereinmay be presented in terms of instructions that operate on data that isstored in a computer memory. Such descriptions and representations areused by those skilled in the art to describe and convey the substance oftheir work to others skilled in the art. In general, an algorithm refersto a self-consistent sequence of steps leading to a desired result,where a “step” refers to a manipulation of physical quantities whichmay, though need not necessarily, take the form of electrical ormagnetic signals capable of being stored, transferred, combined,compared, and otherwise manipulated. It is common usage to refer tothese signals as bits, values, elements, symbols, characters, terms,numbers, or the like. These and similar terms may be associated with theappropriate physical quantities and are merely convenient labels appliedto these quantities.

Unless specifically stated otherwise as apparent from the foregoingdisclosure, it is appreciated that, throughout the foregoing disclosure,discussions using terms such as “processing” or “computing” or“calculating” or “determining” or “displaying” or the like, refer to theaction and processes of a computer system, or similar electroniccomputing device, that manipulates and transforms data represented asphysical (electronic) quantities within the computer system's registersand memories into other data similarly represented as physicalquantities within the computer system memories or registers or othersuch information storage, transmission or display devices.

In a general sense, those skilled in the art will recognize that thevarious aspects described herein which can be implemented, individuallyand/or collectively, by a wide range of hardware, software, firmware, orany combination thereof can be viewed as being composed of various typesof “electrical circuitry.” Consequently, as used herein “electricalcircuitry” includes, but is not limited to, electrical circuitry havingat least one discrete electrical circuit, electrical circuitry having atleast one integrated circuit, electrical circuitry having at least oneapplication specific integrated circuit, electrical circuitry forming ageneral purpose computing device configured by a computer program (e.g.,a general purpose computer configured by a computer program which atleast partially carries out processes and/or devices described herein,or a microprocessor configured by a computer program which at leastpartially carries out processes and/or devices described herein),electrical circuitry forming a memory device (e.g., forms of randomaccess memory), and/or electrical circuitry forming a communicationsdevice (e.g., a modem, communications switch, or optical-electricalequipment). Those having skill in the art will recognize that thesubject matter described herein may be implemented in an analog ordigital fashion or some combination thereof.

The foregoing detailed description has set forth various forms of thedevices and/or processes via the use of block diagrams, flowcharts,and/or examples. Insofar as such block diagrams, flowcharts, and/orexamples contain one or more functions and/or operations, it will beunderstood by those within the art that each function and/or operationwithin such block diagrams, flowcharts, or examples can be implemented,individually and/or collectively, by a wide range of hardware, software,firmware, or virtually any combination thereof. In one form, severalportions of the subject matter described herein may be implemented viaan application specific integrated circuits (ASIC), a field programmablegate array (FPGA), a digital signal processor (DSP), or other integratedformats. However, those skilled in the art will recognize that someaspects of the forms disclosed herein, in whole or in part, can beequivalently implemented in integrated circuits, as one or more computerprograms running on one or more computers (e.g., as one or more programsrunning on one or more computer systems), as one or more programsrunning on one or more processors (e.g., as one or more programs runningon one or more microprocessors), as firmware, or as virtually anycombination thereof, and that designing the circuitry and/or writing thecode for the software and or firmware would be well within the skill ofone of skill in the art in light of this disclosure. In addition, thoseskilled in the art will appreciate that the mechanisms of the subjectmatter described herein are capable of being distributed as a programproduct in a variety of forms, and that an illustrative form of thesubject matter described herein applies regardless of the particulartype of signal bearing medium used to actually carry out thedistribution. Examples of a signal bearing medium include, but are notlimited to, the following: a recordable type medium such as a floppydisk, a hard disk drive, a Compact Disc (CD), a Digital Video Disk(DVD), a digital tape, a computer memory, etc.; and a transmission typemedium such as a digital and/or an analog communication medium (e.g., afiber optic cable, a waveguide, a wired communications link, a wirelesscommunication link (e.g., transmitter, receiver, transmission logic,reception logic, etc.), etc.).

In some instances, one or more elements may be described using theexpression “coupled” and “connected” along with their derivatives. Itshould be understood that these terms are not intended as synonyms foreach other. For example, some aspects may be described using the term“connected” to indicate that two or more elements are in direct physicalor electrical contact with each other. In another example, some aspectsmay be described using the term “coupled” to indicate that two or moreelements are in direct physical or electrical contact. The term“coupled,” however, also may mean that two or more elements are not indirect contact with each other, but yet still co-operate or interactwith each other. It is to be understood that depicted architectures ofdifferent components contained within, or connected with, differentother components are merely examples, and that in fact many otherarchitectures may be implemented which achieve the same functionality.In a conceptual sense, any arrangement of components to achieve the samefunctionality is effectively “associated” such that the desiredfunctionality is achieved. Hence, any two components herein combined toachieve a particular functionality can be seen as “associated with” eachother such that the desired functionality is achieved, irrespective ofarchitectures or intermedial components. Likewise, any two components soassociated also can be viewed as being “operably connected,” or“operably coupled,” to each other to achieve the desired functionality,and any two components capable of being so associated also can be viewedas being “operably couplable,” to each other to achieve the desiredfunctionality. Specific examples of operably couplable include but arenot limited to physically mateable and/or physically interactingcomponents, and/or wirelessly interactable, and/or wirelesslyinteracting components, and/or logically interacting, and/or logicallyinteractable components.

In other instances, one or more components may be referred to herein as“configured to,” “configurable to,” “operable/operative to,”“adapted/adaptable,” “able to,” “conformable/conformed to,” etc. Thoseskilled in the art will recognize that “configured to” can generallyencompass active-state components and/or inactive-state componentsand/or standby-state components, unless context requires otherwise.

While particular aspects of the present disclosure have been shown anddescribed, it will be apparent to those skilled in the art that, basedupon the teachings herein, changes and modifications may be made withoutdeparting from the subject matter described herein and its broaderaspects and, therefore, the appended claims are to encompass withintheir scope all such changes and modifications as are within the truescope of the subject matter described herein. It will be understood bythose within the art that, in general, terms used herein, and especiallyin the appended claims (e.g., bodies of the appended claims) aregenerally intended as “open” terms (e.g., the term “including” should beinterpreted as “including but not limited to,” the term “having” shouldbe interpreted as “having at least,” the term “includes” should beinterpreted as “includes but is not limited to,” etc.). It will befurther understood by those within the art that if a specific number ofan introduced claim recitation is intended, such an intent will beexplicitly recited in the claim, and in the absence of such recitationno such intent is present. For example, as an aid to understanding, thefollowing appended claims may contain usage of the introductory phrases“at least one” and “one or more” to introduce claim recitations.However, the use of such phrases should not be construed to imply thatthe introduction of a claim recitation by the indefinite articles “a” or“an” limits any particular claim containing such introduced claimrecitation to claims containing only one such recitation, even when thesame claim includes the introductory phrases “one or more” or “at leastone” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an”should typically be interpreted to mean “at least one” or “one ormore”); the same holds true for the use of definite articles used tointroduce claim recitations.

In addition, even if a specific number of an introduced claim recitationis explicitly recited, those skilled in the art will recognize that suchrecitation should typically be interpreted to mean at least the recitednumber (e.g., the bare recitation of “two recitations,” without othermodifiers, typically means at least two recitations, or two or morerecitations). Furthermore, in those instances where a conventionanalogous to “at least one of A, B, and C, etc.” is used, in generalsuch a construction is intended in the sense one having skill in the artwould understand the convention (e.g., “a system having at least one ofA, B, and C” would include but not be limited to systems that have Aalone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). In those instances where aconvention analogous to “at least one of A, B, or C, etc.” is used, ingeneral such a construction is intended in the sense one having skill inthe art would understand the convention (e.g., “a system having at leastone of A, B, or C” would include but not be limited to systems that haveA alone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). It will be furtherunderstood by those within the art that typically a disjunctive wordand/or phrase presenting two or more alternative terms, whether in thedescription, claims, or drawings, should be understood to contemplatethe possibilities of including one of the terms, either of the terms, orboth terms unless context dictates otherwise. For example, the phrase “Aor B” will be typically understood to include the possibilities of “A”or “B” or “A and B.”

With respect to the appended claims, those skilled in the art willappreciate that recited operations therein may generally be performed inany order. Also, although various operational flows are presented in asequence(s), it should be understood that the various operations may beperformed in other orders than those which are illustrated, or may beperformed concurrently. Examples of such alternate orderings may includeoverlapping, interleaved, interrupted, reordered, incremental,preparatory, supplemental, simultaneous, reverse, or other variantorderings, unless context dictates otherwise. Furthermore, terms like“responsive to,” “related to,” or other past-tense adjectives aregenerally not intended to exclude such variants, unless context dictatesotherwise.

It is worthy to note that any reference to “one aspect,” “an aspect,”“one form,” or “a form” means that a particular feature, structure, orcharacteristic described in connection with the aspect is included in atleast one aspect. Thus, appearances of the phrases “in one aspect,” “inan aspect,” “in one form,” or “in an form” in various places throughoutthe specification are not necessarily all referring to the same aspect.Furthermore, the particular features, structures or characteristics maybe combined in any suitable manner in one or more aspects.

With respect to the use of substantially any plural and/or singularterms herein, those having skill in the art can translate from theplural to the singular and/or from the singular to the plural as isappropriate to the context and/or application. The varioussingular/plural permutations are not expressly set forth herein for sakeof clarity.

In certain cases, use of a system or method may occur in a territoryeven if components are located outside the territory. For example, in adistributed computing context, use of a distributed computing system mayoccur in a territory even though parts of the system may be locatedoutside of the territory (e.g., relay, server, processor, signal-bearingmedium, transmitting computer, receiving computer, etc. located outsidethe territory).

A sale of a system or method may likewise occur in a territory even ifcomponents of the system or method are located and/or used outside theterritory. Further, implementation of at least part of a system forperforming a method in one territory does not preclude use of the systemin another territory.

All of the above-mentioned U.S. patents, U.S. patent applicationpublications, U.S. patent applications, foreign patents, foreign patentapplications, non-patent publications referred to in this specificationand/or listed in any Application Data Sheet, or any other disclosurematerial are incorporated herein by reference, to the extent notinconsistent herewith. As such, and to the extent necessary, thedisclosure as explicitly set forth herein supersedes any conflictingmaterial incorporated herein by reference. Any material, or portionthereof, that is said to be incorporated by reference herein, but whichconflicts with existing definitions, statements, or other disclosurematerial set forth herein will only be incorporated to the extent thatno conflict arises between that incorporated material and the existingdisclosure material.

In summary, numerous benefits have been described which result fromemploying the concepts described herein. The foregoing description ofthe one or more forms has been presented for purposes of illustrationand description. It is not intended to be exhaustive or limiting to theprecise form disclosed. Modifications or variations are possible inlight of the above teachings. The one or more forms were chosen anddescribed in order to illustrate principles and practical application tothereby enable one of ordinary skill in the art to utilize the variousforms and with various modifications as are suited to the particular usecontemplated. It is intended that the claims submitted herewith definethe overall scope.

Various aspects of the subject matter described herein are set out inthe following numbered clauses:

1. An apparatus comprising a generator configured to provide anelectrical signal waveform to at least one surgical instrument; a tablecomprising information associated with a plurality of wave shapes; andwherein the electrical signal waveform corresponds to at least one waveshape of the plurality of wave shapes of the table.

2. The apparatus of clause 1, wherein the table is stored within thegenerator.

3. The apparatus of clauses 1 or 2, wherein the table is a directdigital synthesis table.

4. The apparatus of clause 3, wherein the direct digital synthesis tableis addressed according to a frequency of the electrical signal waveform.

5. The apparatus of any of clauses 1-4, wherein the informationassociated with the plurality of wave shapes is stored as digitalinformation.

6. The apparatus of any of clauses 1-5, wherein the generator comprisesa DAC circuit and a power amplifier, and wherein the DAC circuit iscoupled to the power amplifier and the DAC circuit provides digitalinput values to the power amplifier associated with a wave shape of theplurality of wave shapes for the electrical signal waveform.

7. The apparatus of any of clauses 1-6, wherein the generator isconfigured to provide the electrical signal waveform to at least twosurgical instruments simultaneously.

8. The apparatus of clause 7, wherein the electrical signal waveformprovided to the at least two surgical instruments comprises at least twowave shapes.

9. The apparatus of clause 8, wherein the generator is configured toprovide the electrical signal waveform that comprises the at least twowave shapes via a single output channel.

10. The apparatus of any of clauses 1-9, wherein the electrical signalwaveform comprises an ultrasonic signal.

11. The apparatus of clause 10, wherein the electrical signal waveformis configured to control at least one of an output current, an outputvoltage, or an output power of an ultrasonic transducer.

12. The apparatus of clause 10 or 11, wherein the electrical signalwaveform is configured to drive at least two vibration modes of anultrasonic transducer of the at least one surgical instrument.

13. The apparatus of any of clauses 1-12, wherein the generator isconfigured to provide the electrical signal waveform to at least twosurgical instruments simultaneously, wherein the electrical signalwaveform comprises an ultrasonic signal and an RF signal.

14. A method of operating a generator, comprising: generating anelectrical signal waveform; providing the generated electrical signalwaveform to at least one surgical instrument; and wherein generating theelectrical signal waveform comprises reading electrical signal waveforminformation from a table comprising information associated with aplurality of wave shapes; and wherein the generated electrical signalwaveform corresponds to at least one wave shape of the plurality of waveshapes of the table.

15. The method of clause 14, wherein the generated electrical signalwaveform corresponds to at least two wave shapes of the plurality ofwave shapes of the table.

16. The method of clause 14 or 15, wherein the electrical signalwaveform comprises an ultrasonic signal.

17. The method of any of clauses 14-16, wherein providing the generatedelectrical signal waveform to the at least one surgical instrumentcomprises providing the electrical signal waveform to at least twosurgical instruments simultaneously.

18. The method of clause 17, wherein the at least two surgicalinstruments comprise at least one ultrasonic surgical instrument and atleast one RF surgical instrument.

19. The method of clauses 14-18, wherein providing the generatedelectrical signal waveform comprises providing the generated waveformvia a single output channel.

20. The method of clauses 14-19, wherein the table is a direct digitalsynthesis table that is addressed according to a frequency of theelectrical signal waveform.

21. An apparatus for operating a surgical instrument, comprising: atleast one surgical instrument configured to receive an electrical signalwaveform from a generator; wherein the electrical signal waveformcorresponds to at least one wave shape of a plurality of wave shapesstored in a table of the generator.

22. The apparatus of clause 21, wherein the at least one surgicalinstrument comprises at least two surgical instruments that receive theelectrical signal waveform simultaneously.

23. The apparatus of clause 22, wherein the electrical signal waveformprovided to the at least two surgical instruments comprises at least twowave shapes.

24. The apparatus of clause 22 or 23, wherein each of the at least twosurgical instruments receive the electrical signal waveform from asingle output channel of the generator.

25. The apparatus of any one of clauses 22-24, wherein one of the atleast two surgical instruments comprises an ultrasonic surgicalcomponent and wherein another of the at least two surgical instrumentscomprises an RF surgical component.

26. The apparatus of any one of clauses 21-25, wherein the electricalsignal waveform comprises a ultrasonic signal.

27. The apparatus of any of clauses 21-26, wherein the electrical signalwaveform is configured to control at least one of an output current, anoutput voltage, or an output power of an ultrasonic transducer of the atleast one surgical instrument.

28. The apparatus of any one of clauses 21-27, wherein the electricalsignal waveform is configured to drive at least two vibration modes ofan ultrasonic transducer of the at least one surgical instrument.

29. The apparatus of any one of clauses 21-28, wherein the generator isconfigured to provide the electrical signal waveform to at least twosurgical instruments simultaneously.

30. A method of generating electrical signal waveforms by a generator,the generator comprising a digital processing circuit, a memory circuitin communication with the digital processing circuit, a digitalsynthesis circuit in communication with the digital processing circuitand the memory circuit, and a digital-to-analog converter (DAC) circuit,the memory circuit defining a lookup table, the method comprising:storing, by the digital processing circuit, phase points of a digitalelectrical signal waveform in the lookup table defined by the memorycircuit, wherein the digital electrical signal waveform is representedby a predetermined number of phase points, wherein the predeterminednumber phase points define a predetermined wave shape; receiving a clocksignal by the digital synthesis circuit, and at each clock cycle:retrieving, by the digital processing circuit, a phase point from thelookup table; and converting, by the DAC circuit, the retrieved phasepoint to an analog signal.

31. The method of clause 30, comprising amplifying, by an amplifier, theanalog signal from an output of the DAC circuit.

32. The method of any one of clause 30 or 31, wherein storing, by thedigital processing circuit, phase points of a digital electrical signalwaveform in the lookup table defined by the memory circuit, comprises:storing, by the digital processing circuit, phase points of multipledigital electrical signal waveforms in corresponding multiple lookuptables defined by the memory circuit or other memory circuits, whereineach of the digital electrical signal waveforms is represented by apredetermined number of phase points, and wherein each of thepredetermined number of phase points defines a different wave shape.

33. The method of any one of clauses 30-32, comprising: receiving, bythe digital processing circuit, a feedback signal associated with tissueparameters; and modifying the predetermined wave shape according to thefeedback signal.

34. The method of any one of clauses 30-33, wherein the digitalelectrical signal waveform represents a RF signal waveform, anultrasonic signal waveform, or a combination thereof.

35. The method of any one of clauses 30-34, wherein the digitalelectrical signal waveform represents a combination of two waveformshaving different amplitudes.

36. The method of any one of clauses 30-35, wherein the digitalelectrical signal waveform represents a combination of two waveformshaving different frequencies.

37. The method of clause 36, wherein the digital electrical signalwaveform represents a combination of two waveforms having of differentamplitudes.

38. The method of any one of clauses 30-37, wherein the predeterminedwave shape is a trapezoid, a sine or cosine wave, a square wave, atriangle wave, or any combinations thereof.

39. The method of any one of clauses 30-38, wherein the digitalelectrical signal waveform is a combined RF and ultrasonic signalwaveform configured to maintain a predetermined ultrasonic frequency.

40. The method of any one of clauses 30-39, wherein the first is acombined RF and ultrasonic waveform configured to deliver maximum poweroutput.

41. A method of generating electrical signal waveforms by a generator,the generator comprising a digital processing circuit, a memory circuitin communication with the digital processing circuit, a digitalsynthesis circuit in communication with the digital processing circuitand the memory circuit, and a digital-to-analog converter (DAC) circuit,the memory circuit defining first and second lookup tables, the methodcomprising: storing, by the digital processing circuit, phase points ofa first digital electrical signal waveform in a first lookup tabledefined by the memory circuit, wherein the first digital electricalsignal waveform is represented by a first predetermined number of phasepoints, wherein the first predetermined number of phase points define afirst predetermined wave shape; storing, by the digital processingcircuit, phase points of a second digital electrical signal waveform ina second lookup table defined by the memory circuit, wherein the seconddigital electrical signal waveform is represented by a secondpredetermined number of phase points, wherein the second predeterminednumber of phase points define a second predetermined wave shape;receiving, by the digital synthesis circuit, a clock signal, and at eachclock cycle: retrieving, by the digital synthesis circuit, a phase pointfrom the first lookup table; retrieving, by the digital synthesiscircuit, a phase point from the second lookup table; and determining, bythe digital processing circuit, whether to switch between the phasepoints of the first and second electrical signal waveforms or tosynchronize the phase points of the first and second electrical signalwaveforms.

42. The method of clause 41, comprising receiving, by the digitalprocessing circuit, a feedback signal associated with tissue parameters.

43. The method of clause 42, comprising: switching between the phasepoint of the first digital electrical signal waveform and the phasepoint of the second digital electrical signal waveform; and converting,by the DAC circuit, the retrieved phase point.

44. The method of clause 42, comprising: synchronizing the phase pointsof the first and second digital electrical signal waveforms to maximizepower delivery per cycle; and converting, by the DAC circuit, thesynchronized phase points.

45. The method of any one of clauses 41-44, wherein the first digitalelectrical signal waveform represents a RF waveform and the seconddigital electrical signal waveform represents an ultrasonic signalwaveform.

46. A generator for generating electrical signal waveforms, thegenerator comprising: a digital processing circuit; a memory circuit incommunication with the digital processing circuit, the memory circuitdefining a lookup table; a digital synthesis circuit in communicationwith the digital processing circuit and the memory circuit, the digitalsynthesis circuit receiving a clock signal; and a digital-to-analogconverter (DAC) circuit; the digital processing circuit configured tostore phase points of a digital electrical signal waveform in the lookuptable defined by the memory circuit, wherein the digital electricalsignal waveform is represented by a predetermined number of phasepoints, wherein the predetermined number phase points define apredetermined wave shape; and retrieve a phase point from the lookuptable at each clock cycle; and the DAC circuit configured to convert theretrieved phase point to an analog signal.

47. The generator of clause 46, comprising an amplifier coupled to theDAC circuit.

48. The generator of clause 46 or 47, wherein the digital synthesiscircuit is a direct digital synthesis (DDS) circuit.

49. The generator of any one of clauses 46-48, comprising a filtercoupled to the output of the DAC circuit.

50. A method of generating electrical signal waveforms by a generator,the generator comprising a digital processing circuit, a memory circuitin communication with the digital processing circuit, the memory circuitdefining first and second lookup tables, a digital synthesis circuit incommunication with the digital processing circuit and the memorycircuit, and a digital-to-analog converter (DAC) circuit, the methodcomprising: storing, by the digital processing circuit, phase points ofa first digital electrical signal waveform in a first lookup tabledefined by the memory circuit, wherein the first digital electricalsignal waveform is represented by a first predetermined number of phasepoints, wherein the first predetermined number of phase points define afirst predetermined wave shape; storing, by the digital processingcircuit, phase points of a second digital electrical signal waveform ina second lookup table defined by the memory circuit, wherein the seconddigital electrical signal waveform is represented by a secondpredetermined number of phase points, wherein the second predeterminednumber of phase points define a second predetermined wave shape; andreceiving a clock signal by the digital synthesis circuit, and at eachclock cycle: retrieving, by the digital synthesis circuit, a phase pointfrom the first lookup table; retrieving, by the digital synthesiscircuit, a phase point from the second lookup table; combining, by thedigital processing circuit, the phase point from the first lookup tablewith the phase point from the second lookup table to generate a combinedphase point; and converting, by the DAC circuit, the combined phasepoint into an analog signal; wherein the analog signal is configured todrive a first and second ultrasonic transducer.

51. The method of clause 50, wherein the first and second digitalelectrical signal waveforms represent first and second digitalultrasonic electrical signal waveforms.

52. The method of clause 50 or 51, comprising combining a radiofrequency (RF) electrical signal waveform with the first and secondultrasonic electrical signal waveforms.

53. The method of any one of clauses 50-52, wherein storing, by thedigital processing circuit, phase points of a digital electrical signalwaveform in the lookup table defined by the memory circuit, comprises:storing, by the digital processing circuit, phase points of multipledigital electrical signal waveforms in corresponding multiple lookuptables defined by the memory circuit or other memory circuits, whereineach of the digital electrical signal waveforms is represented by apredetermined number of phase points, and wherein each of thepredetermined number of phase points defines a different wave shape.

54. The method of any one of clauses 50-53, comprising: receiving, bythe digital processing circuit, a feedback signal associated with tissueparameters; and modifying the first or second predetermined wave shapeaccording to the feedback signal.

55. The method of any one of clauses 50-54, wherein the first or seconddigital electrical signal waveform represents a combination of multiplewaveforms having different amplitudes.

56. The method of any one of clauses 50-55, wherein the first or seconddigital electrical signal waveform represents a combination of multiplewaveforms having different frequencies.

57. The method of clause 56, wherein the first or second digitalelectrical signal waveform represents a combination of multiplewaveforms having of different amplitudes.

58. The method of any one of clauses 50-57, wherein the first or secondpredetermined wave shape is a trapezoid, a sine or cosine wave, a squarewave, a triangle wave, or any combinations thereof.

59. The method of any one of clauses 50-58, wherein the combined phasepoint is configured to maintain a predetermined ultrasonic frequency.

60. The method of any one of clauses 50-59, wherein the combined phasepoint is configured to deliver maximum power output.

61. A method of generating electrical signal waveforms by a generator,the generator comprising a digital processing circuit, a memory circuitin communication with the digital processing circuit, the memory circuitdefining first and second lookup tables, a digital synthesis circuit incommunication with the digital processing circuit and the memorycircuit, and a digital-to-analog converter (DAC) circuit, the methodcomprising: storing, by the digital processing circuit, phase points ofa first digital electrical signal waveform in a first lookup tabledefined by the memory circuit, wherein the first digital electricalsignal waveform is represented by a first predetermined number of phasepoints, wherein the first predetermined number of phase points define afirst predetermined wave shape; storing, by the digital processingcircuit, phase points of a second digital electrical signal waveform ina second lookup table defined by the memory circuit, wherein the seconddigital electrical signal waveform is represented by a secondpredetermined number of phase points, wherein the second predeterminednumber of phase points define a second predetermined wave shape; andreceiving a clock signal by the digital synthesis circuit, and at eachclock cycle: retrieving, by the digital synthesis circuit, a phase pointfrom the first lookup table; retrieving, by the digital synthesiscircuit, a phase point from the second lookup table; combining, by thedigital processing circuit, the phase point from the first lookup tablewith the phase point from the second lookup table to generate a combinedphase point; and converting, by the DAC circuit, the combined phasepoint into an analog signal; wherein the analog signal is configured todrive a plurality of ultrasonic operational modes of an ultrasonicdevice.

62. The method of clause 61, wherein the analog signal is configured toprovide a predetermined tissue effect.

63. The method of clauses 61 or 62, wherein the generator comprises asingle output port and the method further comprises delivering theanalog signal via the single output port.

64. A generator for generating electrical signal waveforms, thegenerator comprising: a digital processing circuit; a memory circuit incommunication with the digital processing circuit, the memory circuitdefining a lookup table; a digital synthesis circuit in communicationwith the digital processing circuit and the memory circuit, the digitalsynthesis circuit receiving a clock signal; and a digital-to-analogconverter (DAC) circuit; the digital processing circuit configured to:store phase points of a first digital electrical signal waveform in afirst lookup table defined by the memory circuit, wherein the firstdigital electrical signal waveform is represented by a firstpredetermined number of phase points, wherein the first predeterminednumber of phase points define a first predetermined wave shape; andstore phase points of a second digital electrical signal waveform in asecond lookup table defined by the memory circuit, wherein the seconddigital electrical signal waveform is represented by a secondpredetermined number of phase points, wherein the second predeterminednumber of phase points define a second predetermined wave shape; at eachclock cycle the digital synthesis circuit is configured to: retrieve aphase point from the first lookup table; retrieve a phase point from thesecond lookup table; the digital processing circuit configured to:combine the phase point from the first lookup table with the phase pointfrom the second lookup table to generate a combined phase point; and theDAC circuit is configured to convert the combined phase point into ananalog signal; wherein the analog signal is configured to drive a firstand second ultrasonic transducer.

65. The generator of clause 64, comprising a non-volatile memory.

66. The generator of clauses 64 or 65, comprising a field programmablegate array (FPGA).

67. The generator of any one of clauses 64-66, comprising an amplifiercoupled to the DAC circuit.

68. The generator of any one of clauses 64-67, wherein the digitalsynthesis circuit is a direct digital synthesis (DDS) circuit.

69. The generator of any one of clauses 64-68, comprising a filtercoupled to an output of the DAC circuit.

70. A method of generating electrical signal waveforms by a generator,the generator comprising a digital processing circuit, a memory circuitin communication with the digital processing circuit, a digitalsynthesis circuit in communication with the digital processing circuitand the memory circuit, and a digital-to-analog converter (DAC) circuit,the memory circuit defining first and second lookup tables, the methodcomprising: storing, by the digital processing circuit, phase points ofa first digital electrical signal waveform in a first lookup tabledefined by the memory circuit, wherein the first digital electricalsignal waveform is represented by a first predetermined number of phasepoints, wherein the first predetermined number of phase points define afirst predetermined wave shape; storing, by the digital processingcircuit, phase points of a second digital electrical signal waveform ina second lookup table defined by the memory circuit, wherein the seconddigital electrical signal waveform is represented by a secondpredetermined number of phase points, wherein the second predeterminednumber of phase points define a second predetermined wave shape;receiving, by the digital synthesis circuit, a clock signal, and at eachclock cycle; retrieving, by the digital synthesis circuit, a phase pointfrom the first lookup table; retrieving, by the digital synthesiscircuit, a phase point from the second lookup table; combining, by thedigital processing circuit, the first and second digital electricalsignal waveforms to form a combined digital electrical signal waveform;and modifying, by the digital processing circuit, the combined digitalelectrical signal waveform to form a modified digital electrical signalwaveform, wherein a peak amplitude of the modified digital electricalsignal waveform does not exceed a predetermined amplitude value.

71. The method of clause 70, comprising defining, by the digitalprocessing circuit, the first or second digital electrical signalwaveform as a radio frequency (RF) drive signal.

72. The method of clause 70 or 71, comprising defining, by the digitalprocessing circuit, the first or second digital electrical signalwaveform as an ultrasonic drive signal.

73. The method of any one of clauses 70-72, comprising determining, bythe digital processing circuit, the peak amplitude of the combineddigital electrical signal waveform while the combined digital electricalsignal waveform is being delivered.

74. The method of clause 73, wherein modifying the combined digitalelectrical signal waveform comprises reducing an amplitude of thecombined digital electrical signal waveform upon determining that thepeak amplitude of the combined digital electrical signal waveform isapproaching while the combined digital electrical signal waveform isbeing delivered.

75. The method of any one of clauses 70-74, wherein the generatorcomprises a direct digital synthesis (DDS) circuit and whereingenerating the first or second digital electrical signal waveformcomprises generating the first or second digital electrical signalwaveform via the DDS circuit.

76. The method of any one of clauses 70-75, comprising determining apeak amplitude of the combined waveform and wherein modifying thecombined waveform comprises modifying the combined waveform based on thepeak amplitude of the combined waveform.

77. The method of any one of clauses 70-76, comprising converting, bythe DAC circuit, the digital electrical signal waveform to an analogsignal and outputting the analog signal.

78. The method of clause 77, wherein the generator comprises atransformer with a plurality of taps, the method comprises outputtingthe analog signal via a single port of the generator.

79. A method of generating electrical signal waveforms by a generator,the generator comprising a digital processing circuit, a memory circuitin communication with the digital processing circuit, a digitalsynthesis circuit in communication with the digital processing circuitand the memory circuit, and a digital-to-analog converter (DAC) circuit,the memory circuit defining first and second lookup tables, the methodcomprising: storing, by the digital processing circuit, phase points ofa first digital electrical signal waveform in a first lookup tabledefined by the memory circuit, wherein the first digital electricalsignal waveform is represented by a first predetermined number of phasepoints, wherein the first predetermined number of phase points define afirst predetermined wave shape; storing, by the digital processingcircuit, phase points of a second digital electrical signal waveform ina second lookup table defined by the memory circuit, wherein the seconddigital electrical signal waveform is represented by a secondpredetermined number of phase points, wherein the second predeterminednumber of phase points define a second predetermined wave shape, whereinthe second digital electrical signal waveform is a function of the firstdigital electrical signal waveform; receiving, by the digital synthesiscircuit, a clock signal, and at each clock cycle; retrieving, by thedigital synthesis circuit, a phase point from the first lookup table;retrieving, by the digital synthesis circuit, a phase point from thesecond lookup table; combining, by the digital processing circuit, thefirst and second digital electrical signal waveforms to form a combineddigital electrical signal waveform; and modifying, by the digitalprocessing circuit, the combined digital electrical signal waveform toform a modified digital electrical signal waveform, wherein a peakamplitude of the modified digital electrical signal waveform does notexceed a predetermined amplitude value.

80. The method of clause 79, comprising extracting, by the digitalprocessing circuit, the first or second digital electrical signalwaveform from the combined digital electrical signal waveform.

81. The method of clause 80, wherein the first or second digitalelectrical signal waveform comprises a wave function, the methodcomprising extracting the wave function from the combined digitalelectrical signal waveform.

82. The method of any one of clauses 80-81, comprising outputting thecombined digital electrical signal waveform via a single port of thegenerator.

83. The method of any one of clauses 80-82, comprising defining, by thedigital processing circuit, the first or second digital electricalsignal waveform as an ultrasonic drive signal.

84. The method of any one of clauses 80-83, comprising defining, by thedigital processing circuit, the first or second digital electricalsignal waveform as a radio frequency (RF) drive signal.

85. A method of generating electrical signal waveforms by a generator,the generator comprising a digital processing circuit, a memory circuitin communication with the digital processing circuit, a digitalsynthesis circuit in communication with the digital processing circuitand the memory circuit, and a digital-to-analog converter (DAC) circuit,the memory circuit defining first and second lookup tables, the methodcomprising: storing, by the digital processing circuit, phase points ofa first digital electrical signal waveform in a first lookup tabledefined by the memory circuit, wherein the first digital electricalsignal waveform is represented by a first predetermined number of phasepoints, wherein the first predetermined number of phase points define afirst predetermined wave shape; storing, by the digital processingcircuit, phase points of a second digital electrical signal waveform ina second lookup table defined by the memory circuit, wherein the seconddigital electrical signal waveform is represented by a secondpredetermined number of phase points, wherein the second predeterminednumber of phase points define a second predetermined wave shape, whereinthe second digital electrical signal waveform is a function of the firstdigital electrical signal waveform; receiving, by the digital synthesiscircuit, a clock signal, and at each clock cycle; retrieving, by thedigital synthesis circuit, a phase point from the first lookup table;retrieving, by the digital synthesis circuit, a phase point from thesecond lookup table; modifying, by the digital processing circuit, afrequency of the first digital electrical signal waveform to form afrequency modified first digital electrical signal waveform; andcombining, by the digital processing circuit, the frequency modifiedfirst digital electrical signal waveform and the second digitalelectrical signal waveform to form a combined digital electrical signalwaveform.

86. The method of clause 85, comprising defining, by the digitalprocessing circuit, the first or second digital electrical signalwaveform as a radio frequency (RF) drive signal.

87. The method of clauses 85-86, comprising defining, by the digitalprocessing circuit, the first or second digital electrical signalwaveform as an ultrasonic drive signal.

88. The method of any one of clauses 85-87, comprising outputting thecombined digital electrical signal waveform via a single port of thegenerator.

89. The method of any one of clauses 85-88, wherein the generatorcomprises a direct digital synthesis (DDS) circuit, wherein generatingthe first digital electrical signal waveform comprises generating thefirst or second digital electrical signal waveform via the DDS circuit.

90. A method of generating electrical signal waveforms by a generator,the generator comprising a processor and a memory in communication withthe processor, the memory defining a first and second table, the methodcomprising: retrieving, by the processor, information from the firsttable defined the memory, wherein the information is associated with afirst wave shape of a first electrical signal waveform for performing asurgical procedure; retrieving, by the processor, information from thesecond table defined in the memory, wherein the information isassociated with a second wave shape of a second electrical signalwaveform for performing a surgical procedure; combining, by theprocessor, the first and second wave shapes to create a combined waveshape of an electrical signal waveform for performing a surgicalprocedure; and delivering the combined wave shape electrical signalwaveform for performing a surgical procedure to a surgical instrument.

91. The method of clause 90, wherein the first table is defined by thefirst memory and the second table is defined by a second memory.

92. The method of clause 90 or 91, wherein the first wave shape isassociated with a radio frequency (RF) electrical signal waveform andthe second wave shape is associated with an ultrasonic electrical signalwaveform.

93. The method of any one of clauses 90-92, wherein the first wave shapeis associated with a first ultrasonic electrical signal waveform and thesecond wave shape is associated with a second ultrasonic electricalsignal waveform.

94. The method of any one of clauses 90-93, comprising creating thefirst and second table by a direct digital synthesis circuit coupled tothe processor.

95. The method of clause 94, comprising: addressing, by the processor,the first table according to a frequency of the first electrical signalwaveform; and addressing, by the processor, the second table accordingto a frequency of the second electrical signal waveform.

96. The method of clause 94, comprising: storing, by the processor, theinformation associated with the first wave shape in the memory; andstoring, by the processor, the information associated with the secondwave shape

97. The method of any one of clauses 90-96, comprising: receiving, bythe processor, a feedback signal associated with tissue parameters; andmodifying the first and second wave shapes according to the feedbacksignal.

98. A method of generating electrical signal waveforms by a generator,the generator comprising a processor and a memory in communication withthe processor, the memory defining a first and second table, the methodcomprising: retrieving, by the processor, information from the firsttable defined the memory, wherein the information is associated with afirst wave shape of a first electrical signal waveform for performing asurgical procedure; retrieving, by the processor, information from thesecond table defined in the memory, wherein the information isassociated with a second wave shape of a second electrical signalwaveform for performing a surgical procedure; and delivering the firstand second electrical signal waveforms for performing a surgicalprocedure to a surgical instrument.

99. The method of clause 98, comprising switching between the first andsecond electrical signal waveforms.

100. The method of clause 98 or 99, comprising: synchronizing the firstand second electrical signal waveforms; and maximizing power deliveredto the surgical instrument.

101. The method of any one of clauses 98-100, wherein the first digitalelectrical signal waveform represents a RF waveform and the seconddigital electrical signal waveform represents an ultrasonic signalwaveform.

102. The method of any one of clauses 98-101, wherein the first waveshape is associated with a first ultrasonic electrical signal waveformand the second wave shape is associated with a second ultrasonicelectrical signal waveform.

103. A method of generating electrical signal waveforms by a generator,the generator comprising a processor and a memory in communication withthe processor, the memory defining a first and second table, the methodcomprising: retrieving, by the processor, information from the firsttable defined the memory, wherein the information is associated with afirst wave shape of a first electrical signal waveform for performing asurgical procedure; retrieving, by the processor, information from thesecond table defined in the memory, wherein the information isassociated with a second wave shape of a second electrical signalwaveform for performing a surgical procedure; and combining, by theprocessor, the first and second wave shapes to create a combined waveshape of an electrical signal waveform for performing a surgicalprocedure; delivering the combined wave shape electrical signal waveformfor performing a surgical procedure to a surgical instrument; andmodifying, by the processor, the combined wave shape of the electricalsignal waveform to form a modified electrical signal waveform, wherein apeak amplitude of the modified electrical signal waveform does notexceed a predetermined amplitude.

104. The method of clause 103, wherein the first wave shape isassociated with a first radio frequency (RF) electrical signal waveformand the second wave shape is associated with a second RF electricalsignal waveform.

105. The method of clause 103 or 104, wherein the first wave shape isassociated with a first ultrasonic electrical signal waveform and thesecond wave shape is associated with a second ultrasonic electricalsignal waveform.

106. The method of any one of clauses 103-105, wherein the first waveshape is associated with a RF electrical signal waveform and the secondwave shape is associated with an ultrasonic electrical signal waveform.

107. The method of any one of clauses 103-106, comprising determining,by the processor, the peak amplitude of the combined electrical signalwaveform while delivering the combined electrical signal waveform to thesurgical instrument.

108. The method of any one of clauses 103-107, comprising reducing anamplitude of the combined electrical signal waveform when the peakamplitude of the combined electrical signal waveform is approaching.

109. The method of any one of clauses 103-108, comprising determining apeak amplitude of the combined electrical signal waveform and modifyingthe combined electrical signal waveform comprises based on thedetermined peak amplitude of the combined electrical signal waveform.

1. A method of generating electrical signal waveforms by a generator,the generator comprising a processor and a memory in communication withthe processor, the memory defining a first and second table, the methodcomprising: retrieving, by the processor, information from the firsttable defined the memory, wherein the information is associated with afirst wave shape of a first electrical signal waveform for performing asurgical procedure; retrieving, by the processor, information from thesecond table defined in the memory, wherein the information isassociated with a second wave shape of a second electrical signalwaveform for performing a surgical procedure; combining, by theprocessor, the first and second wave shapes to create a combined waveshape of an electrical signal waveform for performing a surgicalprocedure; and delivering the combined wave shape electrical signalwaveform for performing a surgical procedure to a surgical instrument.2. The method of claim 1, wherein the first table is defined by thefirst memory and the second table is defined by a second memory.
 3. Themethod of claim 1, wherein the first wave shape is associated with aradio frequency (RF) electrical signal waveform and the second waveshape is associated with an ultrasonic electrical signal waveform. 4.The method of claim 1, wherein the first wave shape is associated with afirst ultrasonic electrical signal waveform and the second wave shape isassociated with a second ultrasonic electrical signal waveform.
 5. Themethod of claim 1, comprising creating the first and second table by adirect digital synthesis circuit coupled to the processor.
 6. The methodof claim 5, comprising: addressing, by the processor, the first tableaccording to a frequency of the first electrical signal waveform; andaddressing, by the processor, the second table according to a frequencyof the second electrical signal waveform.
 7. The method of claim 5,comprising: storing, by the processor, the information associated withthe first wave shape in the memory; and storing, by the processor, theinformation associated with the second wave shape
 8. The method of claim1, comprising: receiving, by the processor, a feedback signal associatedwith tissue parameters; and modifying the first and second wave shapesaccording to the feedback signal.
 9. A method of generating electricalsignal waveforms by a generator, the generator comprising a processorand a memory in communication with the processor, the memory defining afirst and second table, the method comprising: retrieving, by theprocessor, information from the first table defined the memory, whereinthe information is associated with a first wave shape of a firstelectrical signal waveform for performing a surgical procedure;retrieving, by the processor, information from the second table definedin the memory, wherein the information is associated with a second waveshape of a second electrical signal waveform for performing a surgicalprocedure; and delivering the first and second electrical signalwaveforms for performing a surgical procedure to a surgical instrument.10. The method of claim 1, comprising switching between the first andsecond electrical signal waveforms.
 11. The method of claim 9,comprising: synchronizing the first and second electrical signalwaveforms; and maximizing power delivered to the surgical instrument.12. The method of claim 9, wherein the first digital electrical signalwaveform represents a RF waveform and the second digital electricalsignal waveform represents an ultrasonic signal waveform.
 13. The methodof claim 9, wherein the first wave shape is associated with a firstultrasonic electrical signal waveform and the second wave shape isassociated with a second ultrasonic electrical signal waveform.
 14. Amethod of generating electrical signal waveforms by a generator, thegenerator comprising a processor and a memory in communication with theprocessor, the memory defining a first and second table, the methodcomprising: retrieving, by the processor, information from the firsttable defined the memory, wherein the information is associated with afirst wave shape of a first electrical signal waveform for performing asurgical procedure; retrieving, by the processor, information from thesecond table defined in the memory, wherein the information isassociated with a second wave shape of a second electrical signalwaveform for performing a surgical procedure; and combining, by theprocessor, the first and second wave shapes to create a combined waveshape of an electrical signal waveform for performing a surgicalprocedure; delivering the combined wave shape electrical signal waveformfor performing a surgical procedure to a surgical instrument; andmodifying, by the processor, the combined wave shape of the electricalsignal waveform to form a modified electrical signal waveform, wherein apeak amplitude of the modified electrical signal waveform does notexceed a predetermined amplitude.
 15. The method of claim 14, whereinthe first wave shape is associated with a first radio frequency (RF)electrical signal waveform and the second wave shape is associated witha second RF electrical signal waveform.
 16. The method of claim 14,wherein the first wave shape is associated with a first ultrasonicelectrical signal waveform and the second wave shape is associated witha second ultrasonic electrical signal waveform.
 17. The method of claim14, wherein the first wave shape is associated with a RF electricalsignal waveform and the second wave shape is associated with anultrasonic electrical signal waveform.
 18. The method of claim 14,comprising determining, by the processor, the peak amplitude of thecombined electrical signal waveform while delivering the combinedelectrical signal waveform to the surgical instrument.
 19. The method ofclaim 14, comprising reducing an amplitude of the combined electricalsignal waveform when the peak amplitude of the combined electricalsignal waveform is approaching.
 20. The method of claim 14, comprisingdetermining a peak amplitude of the combined electrical signal waveformand modifying the combined electrical signal waveform comprises based onthe determined peak amplitude of the combined electrical signalwaveform.